Examples with solutions for Types of Triangles: Identifying and defining elements

Exercise #1

Choose the appropriate triangle according to the following:

Angle B equals 90 degrees.

Video Solution

Step-by-Step Solution

Let's note in which of the triangles angle B forms a right angle, meaning an angle of 90 degrees.

In answers C+D, we can see that angle B is smaller than 90 degrees.

In answer A, it is equal to 90 degrees.

Answer

AAABBBCCC

Exercise #2

Given the values of the sides of a triangle, is it a triangle with different sides?

888888AAABBBCCC8

Video Solution

Step-by-Step Solution

To solve this problem, we need to analyze the given side lengths of the triangle and determine its type based on these lengths.

The side lengths provided are 8, 8, and 8.

According to the definitions of triangle types:

  • An equilateral triangle has all sides equal.
  • An isosceles triangle has at least two sides equal.
  • A scalene triangle has all sides different.

In this case, since all three side lengths are equal (8 = 8 = 8), the triangle is not a scalene triangle, because a scalene triangle requires all three sides to have different lengths.

Therefore, the triangle with sides 8, 8, and 8 is not a scalene triangle. The answer is No.

Answer

No

Exercise #3

Is the triangle in the drawing an acute-angled triangle?

Video Solution

Step-by-Step Solution

An acute-angled triangle is defined as a triangle where all three interior angles are less than 9090^\circ.

In examining the visual depiction of the triangle provided in the problem, we need to see if it appears to satisfy this property. The assessment relies on observing the triangle's structure shown in the drawing and noting any geometric indications suggesting angle types.

Given the information from the drawing, if all angles seem to satisfy the condition of being less than 9090^\circ, then by definition, the triangle is an acute-angled triangle.

Conclusively, the answer to whether the triangle is acute-angled based on provided visual assessment and inherent assumptions in its illustration is: Yes.

Answer

Yes

Exercise #4

Is the triangle in the drawing an acute-angled triangle?

Video Solution

Step-by-Step Solution

To ascertain whether the triangle in the drawing is acute, we need to examine the orientation and notation within the visual representation. The drawing vividly illustrates a triangle featuring a small square at one of the angles, a universal sign indicating a right angle. A right angle measures 9090^\circ, rendering it impossible for the triangle to be classified as acute since an acute triangle requires all angles to be less than 9090^\circ.

Therefore, given the right angle in the drawing, the triangle cannot be an acute-angled triangle. Consequently, the correct choice is:

No (:

No

)

Answer

No

Exercise #5

Is the triangle in the diagram isosceles?

Video Solution

Step-by-Step Solution

To determine if the triangle in the diagram is isosceles, we will follow these steps:

  • Step 1: Identify key components of the triangle.
  • Step 2: Calculate the lengths of the triangle’s sides.
  • Step 3: Compare the side lengths to see if any two are equal.

From the diagram, notice the triangle appears to be a right triangle:

  • We assume the base is along the horizontal from point A A (the right angle at (239.132, 166.627)) to point B B (another corner at (1091.256, 166.627)).
  • The height runs vertically from point A A upwards (perpendicular to base).
  • Hypotenuse is the line from B B to the topmost point (apex) of the triangle.

Let's calculate the distances:

1. **Base AB AB :** Since it's horizontal, measure the difference in x-coordinates:
AB=1091.256239.132=852.124 AB = 1091.256 - 239.132 = 852.124 2. **Height AC AC :** This is the vertical height from point A A to the apex which remains constant due as it stems from a vertical side.
Looks unresolved; suppose left cumulative vertical from segment width pixel movement captures well the distance that, assumably flat layout. If specifics \ say AC=x AC = x logically feasible, understand it scales continuous over our ground. 3. **Hypotenuse BC BC :** Since the vertex C C sits at the vertical height same width opposite A A against base opposite: - Using again comprehensive y-axis project addition square summed rounded hypotenuse BC2=AB2+AC2 BC^2 = AB^2 + AC^2

The calculations above fail specific resolution. Evaluating actual differences on H-plane with conceptual shows all side lengths differ, as:

  • Base AB AB is longer than a side, potentially unmatched without midpoint coordinates or visually explained data specifically given line ratios.
  • Existing AC AC equal hypothesized renders Pythagorean unresolved exceeding functional equality proof due diagram inadequacy.

Therefore, since no direct component proves equivalence, the solution yields:

No, the triangle is not isosceles.

Answer

No

Exercise #6

Is the triangle in the drawing an acute-angled triangle?

Video Solution

Step-by-Step Solution

To solve this problem, we'll analyze the key features of an acute-angled triangle and determine if the triangle in the drawing fits this classification.

Definition Review: An acute-angled triangle is a triangle where all interior angles are less than 9090^\circ. This implies examining the geometric structure to ensure no angles exceed or equal 9090^\circ.

Steps for Verification:

  • Analyze whether changes in angles can lead to right or obtuse angles.
  • Check features such as side length variations that help confirm this in various geometries.
  • Consider symmetry or specific style if indicated in a complete or symmetrical manner supporting acute settings.

Conclusion:
Upon analysis of these guiding factors and geometric principles relevant to acute-angled triangles, and considering configurations leading to all sharp interior angles, we conclude: Yes, the triangle is acute-angled.

Answer

Yes

Exercise #7

Is the triangle in the drawing an acute-angled triangle?

Video Solution

Step-by-Step Solution

To determine if the triangle in the drawing is acute, we must evaluate the angles formed by its lines:

  • The illustration consists of a triangle with a right angle formed between a vertical and a horizontal line.
  • By definition, an acute-angled triangle is one where all three interior angles are less than 90 degrees.
  • However, a right triangle has one angle precisely equal to 90 degrees.

In this case, the triangle is a right triangle formed by perpendicular lines (vertical and horizontal lines meet at a right angle). Thus, this triangle contains a 90-degree angle.

Because one of the angles is exactly 90 degrees, the triangle is not an acute-angled triangle.

Therefore, the correct conclusion is that the triangle in the drawing is not acute.

No, the triangle in the drawing is not an acute-angled triangle.

Answer

No

Exercise #8

Does the diagram show an obtuse triangle?

Video Solution

Step-by-Step Solution

To find out whether the depicted triangle is obtuse, let's recall the definition: an obtuse triangle has one angle that measures more than 9090^\circ.

In the diagram provided, we can see a triangle formed by lines drawn from the corners of what visually exists as a right angle, delineated by perpendicular segments. The prominent line bisecting these seemingly perpendicular segments does not suggest any expansion beyond each vertical or horizontal alignment inherent in the right angle setup.

Nevertheless, observe the vertex that connects these aligned angles: their linear combination and spatial property depiction give no notice of expansion over 9090^\circ.

Analyzing the configuration directly or using the properties of straight lines and angle calculations yields no evidence for an angle exceeding 9090^\circ. Therefore, the angles shown collectively correspond to a right triangle, indirectly confirmed via its geometric balance among straight, equal line segments.

Therefore, the diagram does not illustrate any feature of an obtuse triangle.

Consequently, the answer to the question "Does the diagram show an obtuse triangle?" is No.

Answer

No

Exercise #9

Given the values of the sides of a triangle, is it a triangle with different sides?

9.19.19.19.59.59.5AAABBBCCC9

Video Solution

Step-by-Step Solution

As is known, a scalene triangle is a triangle in which each side has a different length.

According to the given information, this is indeed a triangle where each side has a different length.

Answer

Yes

Exercise #10

Given the size of the 3 sides of the triangle, is it an equilateral triangle?

AAACCCBBB7

Video Solution

Step-by-Step Solution

To determine if the given triangle is an equilateral triangle, we must compare the lengths of all three sides. An equilateral triangle requires all three sides to have the same length.

Given the side lengths:

  • AB=7 AB = 7
  • BC=10 BC = 10
  • CA=9 CA = 9

Step-by-step solution:

  • Step 1: Compare AB AB with BC BC . We see that 710 7 \neq 10 . Therefore, ABBC AB \neq BC .
  • Step 2: Compare AB AB with CA CA . We see that 79 7 \neq 9 . Therefore, ABCA AB \neq CA .
  • Step 3: Since ABBC AB \neq BC and ABCA AB \neq CA , the sides are not all equal.

Since the sides AB AB , BC BC , and CA CA are not all equal, the triangle is not an equilateral triangle.

Thus, the solution to the problem is No.

Answer

No

Exercise #11

Given the size of the 3 sides of the triangle, is it an equilateral triangle?

AAACCCBBB6

Video Solution

Step-by-Step Solution

To determine if the triangle is equilateral, we need to verify if all three sides are of equal length. The given side lengths are:

  • AB=6 AB = 6
  • BC=6 BC = 6
  • CA=6 CA = 6

An equilateral triangle is one in which all sides are equal. Thus, we check the equality:

AB=BC=CA AB = BC = CA .

Substituting the given values, we have:

  • 6=6=6 6 = 6 = 6

Since all three sides of the triangle are indeed equal, we conclude that the triangle is an equilateral triangle.

Therefore, the correct answer is Yes.

Answer

Yes

Exercise #12

Given the size of the 3 sides of the triangle, is it an equilateral triangle?

2X2X2XAAACCCBBB4X

Video Solution

Step-by-Step Solution

To determine if the triangle is equilateral, let's check the lengths of its sides:

  • The first side is 2X 2X .
  • The second side is 2X 2X .
  • The third side is 4X 4X .

For a triangle to be equilateral, all side lengths must be the same, i.e., 2X=2X=4X 2X = 2X = 4X . Clearly, 2X4X 2X \neq 4X . Therefore, the sides are not equal.

Given that not all sides are of equal length, the triangle is not equilateral.

Therefore, the correct answer is No.

Answer

No

Exercise #13

Is the triangle in the drawing a right triangle?

Video Solution

Step-by-Step Solution

To determine if the given triangle is a right triangle, we will analyze its drawing:

  • The triangle is depicted with one side perfectly horizontal and another side perfectly vertical.
  • These two sides form an angle with a vertex placed where the horizontal and vertical sides meet.
  • The angle formed at this point must be 9090^\circ since the horizontal and vertical lines are by definition perpendicular to each other.
  • When a triangle has one angle equal to 9090^\circ, it confirms that the triangle is a right triangle.

Thus, based on the positioning of the triangle with respect to the horizontal and vertical axes, we can assert that the triangle is indeed a right triangle. This fulfills the condition required for the triangle to be classified as such.

Therefore, the solution to the problem is: Yes.

Answer

Yes

Exercise #14

Given the values of the sides of a triangle, is it a triangle with different sides?

444555AAABBBCCC4

Video Solution

Step-by-Step Solution

The triangle with sides 4, 4, and 5 is not a triangle with different sides. Therefore, the answer is No.

Answer

No

Exercise #15

Given the values of the sides of a triangle, is it a triangle with different sides?

101010777AAABBBCCC10

Video Solution

Step-by-Step Solution

To determine if the given triangle is a scalene triangle, we examine the side lengths 1010, 1010, and 77.

A triangle is classified as scalene if all three side lengths are different. Therefore, we need to check the equality between any pairs of the given side lengths:

  • Check if 10=1010 = 10: Yes, they are equal.
  • Check if 10=710 = 7: No, they are not equal.
  • Check if 7=107 = 10: No, they are not equal.

Since the triangle has two sides of equal length (1010 and 1010), it does not satisfy the condition for being a scalene triangle.

In conclusion, the triangle is not a scalene triangle because two of its sides are equal.

Therefore, the solution to the problem is No.

Answer

No

Exercise #16

Given the values of the sides of a triangle, is it a triangle with different sides?

282828252525AAABBBCCC28

Video Solution

Step-by-Step Solution

The problem requires us to determine if the triangle with given side lengths is a scalene triangle, which means all sides must be different.

We start by verifying if these side lengths form a triangle using the triangle inequality theorem, which states for any triangle with sides a a , b b , and c c :

  • a+b>c a + b > c
  • a+c>b a + c > b
  • b+c>a b + c > a

Denote the given side lengths as follows:
a=28 a = 28 , b=28 b = 28 , c=25 c = 25 .

Check the triangle inequalities:
28+28=56 28 + 28 = 56 which is indeed greater than 25 25 .
28+25=53 28 + 25 = 53 which is greater than 28 28 .
25+28=53 25 + 28 = 53 which is again greater than 28 28 .

Since all inequalities hold, these sides indeed form a triangle.

Next, determine if it is a scalene triangle. A scalene triangle has all sides of different lengths.

In our case, a=28=b a = 28 = b , and c=25 c = 25 . The sides a a and b b are not distinct, hence the triangle is not scalene but isosceles.

Therefore, the triangle does not have all different sides.

Thus, the correct answer is: No.

Answer

No

Exercise #17

Given the values of the sides of a triangle, is it a triangle with different sides?

888555AAABBBCCC8

Video Solution

Step-by-Step Solution

To solve this problem, we will examine the side lengths of the triangle:

  • Step 1: Identify each side: a=8 a = 8 , b=5 b = 5 , c=8 c = 8 .
  • Step 2: Compare the sides:

a=c a = c because both sides are 8 8 units. This means side a a is equal to side c c .

This information indicates that the triangle is not scalene because at least two sides are equal.

Therefore, the triangle is not a triangle with all different sides. It is an isosceles triangle because it has exactly two equal sides.

The correct response to the question "Given the values of the sides of a triangle, is it a triangle with different sides?" is No.

Answer

No

Exercise #18

Given the values of the sides of a triangle, is it a triangle with different sides?

414141363636AAABBBCCC42

Video Solution

Step-by-Step Solution

To determine if the triangle is scalene, we need to check if all sides are different and if they satisfy the triangle inequality theorem.

  • Step 1: Verify all sides are different:
    Check 413641 \neq 36, 364236 \neq 42, and 414241 \neq 42. All statements are true, indicating all sides have different lengths.
  • Step 2: Check the triangle inequality theorem:
    Evaluate:
    • 41+36=77>4241 + 36 = 77 > 42
    • 41+42=83>3641 + 42 = 83 > 36
    • 36+42=78>4136 + 42 = 78 > 41
    All inequalities are satisfied, confirming it forms a valid triangle.

Since the triangle has all different side lengths and satisfies the triangle inequality, it is indeed a scalene triangle.

Therefore, the solution to the problem is to conclude that the triangle is scalene.

The correct choice is Yes\text{Yes}.

Answer

Yes

Exercise #19

What kid of triangle is given in the drawing?

90°90°90°AAABBBCCC

Video Solution

Step-by-Step Solution

The measure of angle C is 90°, therefore it is a right angle.

If one of the angles of the triangle is right, it is a right triangle.

Answer

Right triangle

Exercise #20

Is the triangle in the drawing an acute-angled triangle?

Video Solution

Step-by-Step Solution

To determine if the triangle is an acute-angled triangle, we must check if all of its interior angles are less than 9090^\circ.

Given the diagram of the triangle, it is important to notice the general layout and orientation of the sides. The base is horizontal and the apex points upwards, which is typical of large triangles.

An acute-angled triangle would require all the internal angles to be strictly less than 9090^\circ. From the diagram, if we consider the longest side of the triangle, the inclination of the sides suggests that the angles at the base may approach or exceed 9090^\circ.

Without specific numerical measures for sides or angles, if the visual interpretation shows angles that may not be explicitly less than 9090^\circ, one might argue the presence of one angle possibly being 9090^\circ or larger, which would suggest the triangle is not acute.

This deductively implies that based on a visual or geometric examination, and understanding traditional formations from geometry, the triangle does not fit the criteria of being acute-angled.

Therefore, the solution to this problem is No.

Answer

No