Question

The base BC of an isosceles triangle ABC is greater than each of the equal sides AB = AC. Prove that ∠A > 60 degrees

Answer 1

Answer:

Let the base angles be x°.

The sum of the angles of a triangle is 180°.

i.e., 100+x+x =180⇒2x = 180-100⇒2x=80⇒x =40°

∴ The base angles measure 40°.