Answer:
The answer is below
Explanation:
The measure of the exterior angle 1 of a triangle is equal to the sum of the corresponding interior angles 2 and 3.
This is evident in the Theorem 3 of a triangle
For example
Given a hypothetical triangle, with the following angle QRS, ∠1, ∠2, and ∠3 are interior angles. And ∠4, ∠5, and ∠6 are the three exterior angles.
We have the following ∠4 = ∠2 + ∠3
∠5 = ∠1 + ∠3
∠6 = ∠1 + ∠2