Examples with solutions for Angles in Parallel Lines: Generate a random angle

Exercise #1

a is parallel to b.

Calculate the angles shown in the diagram.

115115115111222333444555666777aaabbb

Video Solution

Step-by-Step Solution

Given that according to the definition, the vertex angles are equal to each other, it can be argued that:

115=2 115=2 Now we can calculate the second pair of vertex angles in the same circle:

1=3 1=3

Since the sum of a plane angle is 180 degrees, angle 1 and angle 3 are complementary to 180 degrees and equal to 65 degrees.

We now notice that between the parallel lines there are corresponding and equal angles, and they are:

115=4 115=4

Since angle 4 is opposite to angle 6, it is equal to it and also equal to 65 degrees.

Another pair of alternate angles are angle 1 and angle 5.

We have proven that:1=3=65 1=3=65

Therefore, angle 5 is also equal to 65 degrees.

Since angle 7 is opposite to angle 5, it is equal to it and also equal to 115 degrees.

That is:

115=2=4=6 115=2=4=6

65=1=3=5=7 65=1=3=5=7

Answer

1, 3 , 5, 7 = 65°; 2, 4 , 6 = 115°

Exercise #2

What is the value of X given that the angles are between parallel lines?

XXX154154154

Video Solution

Step-by-Step Solution

The angle X given to us in the drawing corresponds to an angle that is adjacent to an angle equal to 154 degrees. Therefore, we will mark it with an X.

Now we can calculate:

x+154=180 x+154=180

x=180154=26 x=180-154=26

Answer

26°

Exercise #3

Calculates the size of the angle α \alpha

α40

Video Solution

Step-by-Step Solution

Let's review the definition of alternate angles between parallel lines:

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

Therefore:

α=40 \alpha=40

Answer

40 40

Exercise #4

Given two parallel lines

Calculate the angle α \alpha

α125

Video Solution

Step-by-Step Solution

The angle 125 and the angle alpha are vertically opposite angles, so they are equal to each other.

α=125 \alpha=125

Answer

125 125

Exercise #5

Angle 1 is 20 degrees.

Calculate the size of angle 2.

12

Video Solution

Step-by-Step Solution

Remember the definition of vertically opposite angles:

Vertically opposite angles are formed between two intersecting lines, and they actually have a common vertex and are opposite each other. Vertically opposite angles are equal in size.

Therefore:

1=2=20 1=2=20

Answer

20 20

Exercise #6

Calculate the expression

α+B \alpha+B B30150

Video Solution

Step-by-Step Solution

According to the definition of alternate angles:

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

It can be said that:

α=30 \alpha=30

β=150 \beta=150

And therefore:

30+150=180 30+150=180

Answer

180 180

Exercise #7

According to the drawing

What is the size of the angle? α \alpha ?

120

Video Solution

Step-by-Step Solution

Given that the angle
α \alpha is a corresponding angle to the angle 120 and is also equal to it, thereforeα=120 \alpha=120

Answer

120 120

Exercise #8

Look at the parallelogram in the diagram. Calculate the angles indicated.

3020βα

Video Solution

Step-by-Step Solution

a a is an alternate angle to the angle that equals 30 degrees. That meansα=30 \alpha=30 Now we can calculate: β \beta

As they are adjacent and theredore complementary angles to 180:

18030=150 180-30=150

Angleγ \gamma Is on one side with an angle of 20, which means:

γ=20 \gamma=20

Answer

α=30 \alpha=30 β=150 \beta=150 γ=20 \gamma=20

Exercise #9

What is the size of the missing angle?

80

Video Solution

Answer

100°

Exercise #10

Calculate angle α \alpha given that the lines in the diagram are parallel.

ααα50

Video Solution

Answer

50°

Exercise #11

Calculate X given that the lines in the diagram below are parallel.

X70

Video Solution

Answer

110

Exercise #12

Calculate the size of the missing angle given that lines a and b are parallel.

118118118646464aaabbb

Video Solution

Answer

64

Exercise #13

Calculate the missing angle given that lines a and b are parallel.

118118118646464aaabbb

Video Solution

Answer

64

Exercise #14

Calculate the angle α \alpha given that the lines in the diagram below are parallel.

ααα40

Video Solution

Answer

40°

Exercise #15

The lines a a and b b are parallel.

What is the value of the angle C C ?

137137137bbbaaaDC

Video Solution

Answer

137°

Exercise #16

Calculate the angle α \alpha given that the lines in the diagram are parallel.

ααα55

Video Solution

Answer

125°

Exercise #17

Calculate the angle α \alpha given that the lines in the diagram below are parallel.

ααα120

Video Solution

Answer

60°

Exercise #18

The lines a and b are parallel.

Calculate the angle indicated in red.

aaabbb64118

Video Solution

Answer

118

Exercise #19

The lines shown below are parallel.

Calculate the size of angle α \alpha and indicate the relationship between the two angles.

70

Video Solution

Answer

110, co-interior angles.

Exercise #20

Calculate the angles indicated in the figure given that a and b are parallel.

137137137bbbaaaCD

Video Solution

Answer

C-43 D-137