In the following diagram (used in Exercise #5), ∠ACD is known as an exterior angle of the triangle. ∠1 and ∠2 are known as remote interior angles relative to ∠ACD.
Explain why m∠ACD = m∠1+ m∠2 why does it make sense to claim that an exterior angle to a triangle must always be greater in measure than either of its two remote interior angles?
