Examples with solutions for Angles in Parallel Lines: Three parallel lines

Exercise #1

Given three parallel lines

Findα,β \alpha,\beta

αααβββ383838140

Video Solution

Step-by-Step Solution

We will mark the angle opposite the vertex of 38 with the number 1, therefore, angle 1 is equal to 38 degrees.

We will mark the angle adjacent to angle β \beta with the number 2. And since angle 2 corresponds to the angle 140, angle 2 will be equal to 140 degrees

Since we know that angle 1 is equal to 38 degrees we can calculate the angleα \alpha α=18038=142 \alpha=180-38=142

Now we can calculate the angleβ \beta

180 is equal to angle 2 plus the other angleβ \beta

Since we are given the size of angle 2, we replace the equation and calculate:

β=180140=40 \beta=180-140=40

Answer

α=142 \alpha=142 β=40 \beta=40

Exercise #2

Look at the diagram below.

Calculate the size of angle ABC.

AAABBBHHHCCCDDD92131

Video Solution

Step-by-Step Solution

In the drawing before us, we can see three parallel lines and two lines that intersect them.

We are asked to find the size of angle ABC,

We can identify that the angle is actually composed of two angles, angle ABH and CBH.

In fact, we will calculate the size of each angle separately and combine them.

Angle A is an alternate angle to angle ABH, and since alternate angles are equal, angle ABH equals 92.

Angle CBH is supplementary to angle DCB, supplementary angles equal 180, therefore we can calculate:

HBC=180DCB HBC = 180-DCB

HBC=180131 HBC = 180 - 131

HBC=49 HBC = 49

Now that we have found angles ABH and CBH, we can add them to find angle ABC

ABH+CBH=ABC ABH + CBH = ABC

92+49=141 92 + 49 = 141

Answer

141 141

Exercise #3

Look at the angles formed by parallel lines in the figure below:

646464XXX757575

What is the value of X?

Video Solution

Step-by-Step Solution

Given that the three lines are parallel:

The 75 degree angle is an alternate angle with the one adjacent to angle X on the right side, and therefore is also equal to 75 degrees.

The 64 degree angle is an alternate angle with the one adjacent to angle X on the left side, and therefore is also equal to 64 degrees.

Now we can calculate:

64+x+75=180 64+x+75=180

x=1807564=41 x=180-75-64=41

Answer

41°

Exercise #4

Lines a, b, and c are parallel.

How big is angle α \alpha ?

aaabbbccc14050α

Video Solution

Answer

90

Exercise #5

a,b,c parallel to one another

Find a α \alpha

aaabbbccc8329α

Video Solution

Answer

68

Exercise #6

Since a,b,c are parallel

Find a α \alpha

aaabbbcccα4539

Video Solution

Answer

96

Exercise #7

Since a,b,c are parallel

Find a α \alpha

aaabbbccc2974α

Video Solution

Answer

77

Exercise #8

Calculate the value of the angles. α,β \alpha,\beta

AAABBBCCC25αβ

Video Solution

Answer

α=155 \alpha=155 β=155 \beta=155

Exercise #9

Angle ABC equals 135 degrees.

Angle A equals 95 degrees.

Calculate angle BCD.

AAABBBHHHDDDCCC13595

Video Solution

Answer

40 40

Exercise #10

According to the figure, calculate the angle CDE

10342ABCDEF

Video Solution

Answer

145 145

Exercise #11

According to the figure, calculate the angle CEF

AAABBBCCCDDDEEEFFF2222.5

Video Solution

Answer

22.5 22.5

Exercise #12

Calculate the size of angle α \alpha according to the data in the diagram below:

AAABBBCCCDDDEEE230α35

Video Solution

Answer

85 85

Exercise #13

According to the figure, calculate the angle α \alpha

ααα282828

Video Solution

Answer

152 152

Exercise #14

Angle BCE equals 198 degrees.

Calculate the angle CEF.

AAABBBCCCDDDEEEFFFHHH32

Video Solution

Answer

166 166 degrees

Exercise #15

Calculate the value of the expression α+β \alpha+\beta

αααβββ27

Video Solution

Answer

54 54

Exercise #16

Lines a, b, and c are parallel.

Calculate the angle marked (?).

aaacccbbb125108?

Video Solution

Answer

17

Exercise #17

Given a,b,c parallel lines

Find a α \alpha

ααα130130130cccaaabbb48

Video Solution

Answer

82

Exercise #18

Given a,b,c parallels

Find a α \alpha

aaabbbccc115α7853

Video Solution

Answer

49

Exercise #19

c ,b ,a parallel.

Find a α \alpha

aaabbbccc130°45°α

Video Solution

Answer

85

Exercise #20

a,b,c parallel

Find X

aaabbbccc25383x

Video Solution

Answer

39