Parts of a Triangle Practice Problems - Sides, Perimeter & Types

Master triangle parts with interactive practice problems. Learn to identify sides, calculate perimeter, classify triangle types, and apply the triangle inequality theorem.

📚Master Triangle Parts with Step-by-Step Practice
  • Calculate triangle perimeter by adding all three sides together
  • Classify triangles as equilateral, isosceles, or scalene based on side lengths
  • Apply the triangle inequality theorem to determine valid triangle formations
  • Identify relationships between side lengths and opposite angles
  • Solve for unknown side lengths in equilateral triangles using perimeter
  • Determine if three given measurements can form a valid triangle

Understanding The sides or edges of a triangle

Complete explanation with examples

The sides of a triangle

Every triangle has three sides. That also works the other way around - if we see a shape with tree sides, it's a triangle.

types of triangles based on the sides:

The sides allow us to classify the different types of triangles according to their size:

  • Equilateral: All sides are equal, leading to equal angles.
  • Isosceles: Two sides are equal, with base angles also equal.
  • Scalene: All sides are different lengths, with all angles unique.
Perimeter of a Triangle

Like every polygon, the sides of a triangle form its perimeter. To find the perimeter of a triangle, simply add the lengths of all three sides.

A1 - Sides of a triangle
Relation between the sides and the angles in a triangle

In a triangle, there’s a direct relationship between the length of a side and the size of the angle across from it:
The Longer Side will always be in the opposite side of the larger Angle, and the shorter side will always be in the opposite side of the smaller Angle.

Can every three lines form a triangle?

In any triangle, the sum of the two shorter sides must always be greater than the length of the third side. This rule, known as the Triangle Inequality Theorem, ensures that the sides can actually form a closed triangle. For example, if the two shorter sides are not greater than the third, the sides would lie flat rather than forming a triangle. This principle is crucial in determining whether a set of side lengths can create a valid triangle.

Detailed explanation

Practice The sides or edges of a triangle

Test your knowledge with 33 quizzes

Look at the triangle ABC below.

Which of the line segments is the median?

AAABBBCCCGGGHHHFFFDDDEEE

Examples with solutions for The sides or edges of a triangle

Step-by-step solutions included
Exercise #1

True or false:

DE not a side in any of the triangles.
AAABBBCCCDDDEEE

Step-by-Step Solution

To solve the problem of determining whether DE is not a side in any of the triangles, we will methodically identify the triangles present in the diagram and examine their sides:

  • Identify triangles in the diagram. The diagram presented forms a right-angled triangle ABC with additional lines forming smaller triangles within.
  • Triangles formed: Triangle ABC (major triangle), Triangle ABD, Triangle BEC, and Triangle DBE.
  • Let's examine the sides of these triangles:
    • Triangle ABC has sides AB, BC, and CA.
    • Triangle ABD has sides AB, BD, and DA.
    • Triangle BEC has sides BE, EC, and CB.
    • Triangle DBE has sides DB, BE, and ED.
  • Notice that while point D is used, the segment DE is only part of line BE and isn't listed as a direct side of any triangle.

Therefore, the claim that DE is not a side in any of the triangles is indeed correct.

Hence, the answer is True.

Answer:

True

Video Solution
Exercise #2

Is DE side in one of the triangles?
AAABBBCCCDDDEEE

Step-by-Step Solution

Since line segment DE does not correspond to a full side of any of the triangles present within the given geometry, we conclude that the statement “DE is a side in one of the triangles” is Not true.

Answer:

Not true

Video Solution
Exercise #3

The triangle ABC is shown below.

To which side(s) are the median and the altitude drawn?

AAABBBCCCDDDEEEFFF

Step-by-Step Solution

To solve the problem of identifying to which side of triangle ABC ABC the median and the altitude are drawn, let's analyze the diagram given for triangle ABC ABC .

  • We acknowledge that a median is a line segment drawn from a vertex to the midpoint of the opposite side. An altitude is a line segment drawn from a vertex perpendicular to the opposite side.
  • Upon reviewing the diagram of triangle ABC ABC , line segment AD AD is a reference term. It appears to meet point C C in the middle, suggesting it's a median, but it also forms right angles suggesting it is an altitude.
  • Given the placement and orientation of AD AD , it is perpendicular to line BC BC (the opposite base for the median from A A ). Therefore, this line is both the median and the altitude to side BC BC .

Thus, the side to which both the median and the altitude are drawn is BC.

Therefore, the correct answer to the problem is the side BC BC , corresponding with choice Option 2: BC \text{Option 2: BC} .

Answer:

BC

Exercise #4

The triangle ABC is shown below.

Which line segment is the median?

AAABBBCCCDDDEEEFFF

Step-by-Step Solution

To solve this problem, we need to identify the median in triangle ABC:

  • Step 1: Recall the definition of a median. A median is a line segment drawn from a vertex to the midpoint of the opposite side.
  • Step 2: Begin by evaluating each line segment based on the definition.
  • Step 3: Identify points on triangle ABC:
    • AD is from A to a point on BC.
    • BE is from B to a point on AC.
    • FC is from F to a point on AB.
  • Step 4: Determine if these points (D, E, F) are midpoints:
    • Since BE connects B to E, and E is indicated to be the midpoint of segment AC (as shown), BE is the median.
    • AD and FC, by visual inspection, do not connect to midpoints on BC or AB respectively.

Therefore, the line segment that represents the median is BE BE .

Thus, the correct answer is: BE

Answer:

BE

Video Solution
Exercise #5

Look at triangle ABC below.

What is the median of the triangle and to which side is it drawn?

AAABBBCCCDDDEEE

Step-by-Step Solution

A median of a triangle is a line segment that connects a vertex to the midpoint of the opposite side. In triangle ABC \triangle ABC , we need to identify such a median from the diagram provided.

Step 1: Observe the diagram to identify the midpoint of each side.

Step 2: It is given that point E E is located on side AC AC . If E E is the midpoint of AC AC , then any line from a vertex to point E E would be a median.

Step 3: Check line segment BE BE . This line runs from vertex B B to point E E .

Step 4: Since E E is labeled as the midpoint of AC AC , line BE BE is the median of ABC \triangle ABC drawn to side AC AC .

Therefore, the median of the triangle is BE BE for AC AC .

Answer:

BE for AC

Frequently Asked Questions

How do you find the perimeter of a triangle?

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To find the perimeter of a triangle, simply add the lengths of all three sides together. For example, if a triangle has sides of 4 cm, 3 cm, and 5 cm, the perimeter is 4 + 3 + 5 = 12 cm.

What are the three types of triangles based on their sides?

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The three types are: 1) Equilateral - all three sides are equal, 2) Isosceles - two sides are equal, 3) Scalene - all three sides are different lengths. Each type also has corresponding angle properties.

What is the triangle inequality theorem?

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The triangle inequality theorem states that the sum of any two sides of a triangle must be greater than the length of the third side. This rule determines whether three given lengths can actually form a valid triangle.

How do you check if three sides can form a triangle?

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Check all three combinations: add the two shorter sides and verify the sum is greater than the longest side. For example, with sides 5, 7, and 10: check that 5+7>10, 7+10>5, and 5+10>7.

What is the relationship between triangle sides and angles?

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In any triangle, the longest side is always opposite the largest angle, and the shortest side is opposite the smallest angle. This direct relationship helps identify angle sizes based on side lengths.

How do you find the side length of an equilateral triangle from its perimeter?

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Since all three sides are equal in an equilateral triangle, divide the perimeter by 3. For example, if the perimeter is 21 cm, each side is 21 ÷ 3 = 7 cm.

Can a triangle have sides of 3 cm, 4 cm, and 8 cm?

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No, these sides cannot form a triangle. When you add the two shorter sides (3 + 4 = 7), the sum is less than the third side (8 cm), violating the triangle inequality theorem.

What are the parts of a triangle?

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A triangle has three main parts: three sides (edges), three vertices (corners), and three angles. The sides connect the vertices and form the perimeter, while angles are formed where two sides meet.

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