Question

if the base of an isosceles triangle is produced on both sides, prove that the exterior angles so formed are equal to each other.

Answer 1

[GIVEN]- Base BC of ∆ABC is produced (_∆_) to D and E both the sides. [TO PROVE]- Angle ABD = Angle ACE. [PROOF]- In Isosceles ∆ABC--- Angle DBC = Angle BCE =180° . So, (Angle DBC - Angle ABC) = (Angle BCE - Angle ACB) => 180° - Angle ABC = 180° - Angle ACB = > Angle ABD = Angle ACE [•.• Angle ABC= Angle ACB] Hence, proved.