Question

I need help on these problems please

Answer 1

The remote interior angles of a triangle are basically the two angles that do not share a vertex with and are opposite to the exterior angle.

5. ∠1 and ∠2
6. ∠2 and ∠3
7. ∠1 and ∠3

Because the exterior angle of a triangle is equal to the remote interior angles we can set up the following equations:
8.
$x + 80 = 105 \\ x = 105 - 80 \\ x = 25$
9.
$x + 72 = 135 \\ x = 135 - 72 \\ x = 63$