Question

Find the measure of angle X. The horizontal lines are parallel. HINT: The sum

of all interior angles in a triangle is 180 degrees.

Answer 1

Answer: x = 112 (choice D)

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Step-by-step explanation:

The angle adjacent and supplementary to the 107 degree angle is 73 degrees because 107+73 = 180.

Or you could say 180 - 107 = 73.

The base angles of the upper isosceles triangle are 73 degrees each, which means the third remaining angle (let's call it y for now) is

73+73+y = 180

146+y = 180

y = 180-146

y = 34

Refer to the diagram below. Notice how the 34 degree angle shows up twice because we have vertical angles. Consequently, the base angles of the bottom isosceles triangle are y = 34 degrees each

We can now solve for x

y+y+x = 180

34+34+x = 180

68+x = 180

x = 180-68

x = 112, so the answer is choice D