Point D belongs to the interior of triangle ABC. prove that m (∠A).

Given:

ABC is a triangle.

D is a point belonging to the inner region of the triangle.

Prove:

∠A <∠D.

Proof:

Consider a triangle ABC, the condition says that point D lies inside the area of the triangle. We connect with points A and C, we get a segment AD and AC. The segment AD divides ∠A into two ∠DAC and ∠DAB, the same with ∠C. It turns out that two ∠ have decreased, which means the third has increased. Hence ∠ D> ∠A. Q.E.D.

Answer: ∠ D> ∠A.