Answer:
15) x = 155°
16) x = 115°
Step-by-step explanation:
The theorem that relates an exterior angle of a triangle to the opposite (remote) interior angles is helpful for these problems. It says the exterior angle is equal to the sum of the remote interior angles.
<h3>15)</h3>
Remove the altitude line and consider the interior angle of the triangle next to the exterior angle marked 60°. That interior angle will be ...
180° -60° = 120°
Then the angle we just found and the one marked 35° are "remote" to the exterior angle marked x. The theorem cited at the beginning tells us ...
x = 35° +120°
x = 155°
<h3>16)</h3>
Extend the left side of the "parallelogram" (the side with the arrow) upward until it meets the top horizontal line. This cuts off a triangle with an exterior angle marked x, an interior angle marked 50°, and another remote interior angle at the top edge of that triangle.
The opposite angles of a parallelogram are congruent, so the external angle to the triangle at the top edge will be x, and the adjacent interior angle in the triangle will be (180° -x).
The exterior angle (x) is equal to the sum of the remote interior angles (50° and (180° -x)), so we have ...
x = 50 +(180 -x)
2x = 230 . . . . . . add x, simplify
x = 115 . . . . . . . divide by 2
The measure of the angles marked x is 115°.