Question

(d) problem 20: select the value of y in terms of x. after you pick your answer press go. a. y = 138 - x b. y = x - 42 c. y = 138 + x d. y = x - 138 e. y = 42 + x

Explanation:

Step1: Find adjacent - interior angle

The adjacent - interior angle to the $138^{\circ}$ exterior angle is $180 - 138=42^{\circ}$ since they are supplementary angles.

Step2: Use angle - sum property of triangle

In a triangle, the sum of interior angles is $180^{\circ}$. So $y + 42+x=180 - 180$. Rearranging gives $y=42 + x$.

Answer:

E. $y = 42 + x$