Examples with solutions for Angles in Parallel Lines: Identifying and defining elements

Exercise #1

Is it possible to have two adjacent angles, one of which is obtuse and the other right?

Video Solution

Step-by-Step Solution

Remember the definition of adjacent angles:

Adjacent angles always complement each other up to one hundred eighty degrees, that is, their sum is 180 degrees.

This situation is impossible since a right angle equals 90 degrees, an obtuse angle is greater than 90 degrees.

Therefore, together their sum will be greater than 180 degrees.

Answer

No

Exercise #2

In which of the diagrams are the angles α,β  \alpha,\beta\text{ } vertically opposite?

Step-by-Step Solution

Remember the definition of angles opposite by the vertex:

Angles opposite by the vertex are angles whose formation is possible when two lines cross, and they are formed at the point of intersection, one facing the other. The acute angles are equal in size.

The drawing in answer A corresponds to this definition.

Answer

αααβββ

Exercise #3

a a is parallel to

b b

Determine which of the statements is correct.

αααβββγγγδδδaaabbb

Video Solution

Step-by-Step Solution

Let's review the definition of adjacent angles:

Adjacent angles are angles formed where there are two straight lines that intersect. These angles are formed at the point where the intersection occurs, one next to the other, and hence their name.

Now let's review the definition of collateral angles:

Two angles formed when two or more parallel lines are intersected by a third line. The collateral angles are on the same side of the intersecting line and even are at different heights in relation to the parallel line to which they are adjacent.

Therefore, answer C is correct for this definition.

Answer

β,γ \beta,\gamma Colateralesγ,δ \gamma,\delta Adjacent

Exercise #4

Identify the angle shown in the figure below?

Step-by-Step Solution

Remember that adjacent angles are angles that are formed when two lines intersect one another.

These angles are created at the point of intersection, one adjacent to the other, and that's where their name comes from.

Adjacent angles always complement one another to one hundred and eighty degrees, meaning their sum is 180 degrees. 

Answer

Adjacent

Exercise #5

Identify the angles shown in the diagram below?

Step-by-Step Solution

Let's remember that vertical angles are angles that are formed when two lines intersect. They are are created at the point of intersection and are opposite each other.

Answer

Vertical

Exercise #6

Which type of angles are shown in the figure below?

Step-by-Step Solution

Alternate angles are a pair of angles that can be found on the opposite side of a line that cuts two parallel lines.

Furthermore, these angles are located on the opposite level of the corresponding line that they belong to.

Answer

Alternate

Exercise #7

Which type of angles are shown in the diagram?

Step-by-Step Solution

First let's remember that corresponding angles can be defined as a pair of angles that can be found on the same side of a transversal line that intersects two parallel lines.

Additionally, these angles are positioned at the same level relative to the parallel line to which they belong.

Answer

Corresponding

Exercise #8


Look at the rectangle ABCD below.

What type of angles are labeled with the letter A in the diagram?

What type are marked labeled B?

AAABBBCCCDDDBBAA

Step-by-Step Solution

Let's remember the definition of corresponding angles:

Corresponding angles are angles located on the same side of the line that cuts through the two parallels and are also situated at the same level with respect to the parallel line to which they are adjacent.

It seems that according to this definition these are the angles marked with the letter A.

Let's remember the definition of adjacent angles:

Adjacent angles are angles whose formation is possible in a situation where there are two lines that cross each other.

These angles are formed at the point where the intersection occurs, one next to the other, and hence their name.

Adjacent angles always complement each other to one hundred eighty degrees, that is, their sum is 180 degrees.

It seems that according to this definition these are the angles marked with the letter B.

Answer

A - corresponding

B - adjacent

Exercise #9

Look at the rhombus in the figure.

What is the relationship between the marked angles?

BAAB

Step-by-Step Solution

Let's remember the different definitions of angles:

Corresponding angles are angles located on the same side of the line that intersects the two parallels and are also situated at the same level with respect to the parallel line they are adjacent to.

Therefore, according to this definition, these are the angles marked with the letter A

Alternate angles are angles located on two different sides of the line that intersects two parallels, and which are also not at the same level with respect to the parallel they are adjacent to.

Therefore, according to this definition, these are the angles marked with the letter B

Answer

A - corresponding; B - alternate

Exercise #10

Identify the angles marked in the figure below given that ABCD is a trapezoid:

AAABBBCCCDDDEEEFFF

Step-by-Step Solution

Given that ABCD is a trapezoid, we can deduce that lines AB and CD are parallel to each other.

It is important to note that alternate angles are defined as a pair of angles that can be found in the opposite aspect of a line intended to intersect two parallel lines.

Additionally, these angles are positioned at opposite levels relative to the parallel line to which they belong.

Answer

Alternates

Exercise #11

Identify the angles in the image below:

Step-by-Step Solution

Given that the three lines are parallel to one another, one should note that corresponding angles can be defined as a pair of angles that can be found on the same side of a line intended to intersect two parallel lines.

Additionally, these angles are located on the same level relative to the line they correspond to.

Answer

Corresponding

Exercise #12

What angles are described in the drawing?

Step-by-Step Solution

Since the angles are not on parallel lines, none of the answers are correct.

Answer

Ninguna de las respuestas

Exercise #13

Identify the angles shown in the diagram below?

Step-by-Step Solution

Given that we are not provided with any data related to the lines, we cannot determine whether they are parallel or not.

As a result, none of the options are correct.

Answer

None of the above

Exercise #14

The lines a and b are parallel.

What are the corresponding angles?

αααβββγγγδδδaaabbb

Video Solution

Step-by-Step Solution

Given that line a is parallel to line b, let us remind ourselves of the definition of corresponding angles between parallel lines:

Corresponding angles are angles located on the same side of the line that intersects the two parallels and are also situated at the same level with respect to the parallel line to which they are adjacent.

Corresponding angles are equal in size.

According to this definition α=β \alpha=\beta and as such they are the corresponding angles.

Answer

α,β \alpha,\beta

Exercise #15

What are alternate angles of the given parallelogram ?

αααγγγδδδβββxxx

Step-by-Step Solution

To solve the question, we must first remember that a parallelogram has two pairs of opposite sides that are parallel and equal.

That is, the top line is parallel to the bottom one.

From this, it is easy to identify that angle X is actually an alternate angle of angle δ, since both are on different sides of parallel straight lines.

Answer

δ,χ \delta,\chi

Exercise #16

If two adjacent angles are not equal to one another, then one of them is obtuse and the other is acute.

Video Solution

Step-by-Step Solution

The answer is correct because the sum of two acute angles will be less than 180 degrees and the sum of two obtuse angles will be greater than 180 degrees

Answer

True

Exercise #17

Is it possible to have two adjacent angles that are both right angles?

Step-by-Step Solution

To solve this problem, we'll consider the definition and properties of right and adjacent angles.

  • Step 1: Definition of Adjacent Angles
    Adjacent angles share a common vertex and a common side, but do not overlap. They are typically formed when two lines intersect.
  • Step 2: Characteristics of Right Angles
    A right angle measures 9090^\circ. If two such angles are placed adjacent to each other, their total is 90+90=18090^\circ + 90^\circ = 180^\circ.
  • Step 3: Geometric Interpretation
    Two right angles, each 9090^\circ, can indeed share a common side, forming a straight line (also known as a linear pair). This illustrates that it is possible to have two adjacent right angles.

When visualized, these two right angles can be seen as forming a straight angle or line. This conclusion can be confirmed by considering the total degrees along a straight line: 180180^\circ.

Therefore, it is indeed possible for two adjacent angles to both be right angles. These right angles together will form a straight line.

Therefore, the solution to the problem is Yes.

Answer

Yes

Exercise #18

Is it possible to have two adjacent angles that are both obtuse?

Step-by-Step Solution

To solve this problem, let's analyze the properties of the angles involved:

  • Definition of obtuse angle: An angle is obtuse if it is greater than 9090^\circ and less than 180180^\circ.
  • Definition of adjacent angles: Adjacent angles share a common side and vertex, and typically form a straight line, summing to 180180^\circ.

Let's consider two adjacent angles, A\angle A and B\angle B, whose sum is 180180^\circ, because they form a straight line.

If A\angle A is obtuse, then A>90\angle A > 90^\circ.

Similarly, if B\angle B is obtuse, then B>90\angle B > 90^\circ.

Adding these inequalities, we would have:

A+B>90+90=180\angle A + \angle B > 90^\circ + 90^\circ = 180^\circ.

However, since the sum of the angles forming a straight line is exactly 180180^\circ, having both angles greater than 9090^\circ is impossible as their sum would exceed 180180^\circ. This contradicts the supplementary angle requirement for adjacent angles on a straight line.

Conclusion: Thus, it is not possible to have two adjacent angles that are both obtuse.

Therefore, the answer to the problem is No.

Answer

No

Exercise #19

Is it possible to have two adjacent angles, one of which is obtuse and the other straight?

Step-by-Step Solution

To determine if it is possible to have two adjacent angles, one of which is obtuse and the other is straight, we proceed as follows:

  • By definition, an adjacent angle shares a common side and vertex with another.
  • A straight angle is always 180180^\circ.
  • An obtuse angle is any angle greater than 9090^\circ but less than 180180^\circ.

Now, let's analyze the mathematical feasibility:

A straight angle, being 180180^\circ, means that any angle adjacent to it must share the same vertex and a common side, forming the potential sum of angles at that vertex. However, two angles adjacent to each other should sum up to remain within a feasible geometric angle.

If one angle is straight (180180^\circ), the total sum along one side is 180180^\circ. Adding an obtuse angle means we attempt to exceed or equal 360360^\circ (forming a complete circle), which isn't geometrically possible within a plane for two adjacent angles. An adjacent, obtuse angle would result in an implausible scenario since:

  • The obtuse angle, when combined with a straight angle, exceeds a complete line (180180^\circ).

Thus, both forming traditional planar geometry angles of exactly one line with shared points isn't feasible.

Therefore, it is not possible to have a straight angle as an adjacent pair with an obtuse angle.

No.

Answer

No.

Exercise #20

The sum of the adjacent angles is 180

Step-by-Step Solution

To determine if the statement that "the sum of the adjacent angles is 180" is true, follow these steps:

  • Step 1: Define Adjacent Angles

    Adjacent angles are two angles that have a common vertex and a common side but do not overlap. In geometry, when these angles form a straight line, they are known as a linear pair.

  • Step 2: Apply the Linear Pair Theorem

    The Linear Pair Theorem states that if two angles are adjacent and form a linear pair (i.e., the non-common sides form a straight line), then these angles are supplementary. This means that their sum is 180180^\circ.

  • Step 3: Conclusion

    Therefore, when adjacent angles form a linear pair on a straight line, their sum is indeed 180180^\circ.

This validates the statement that "the sum of the adjacent angles is 180" for linear pairs, making the statement True.

This corresponds to the answer choice stating: True.

Answer

True