Question

measure of this angle.
4. The vertical angle of an isosceles triangle is 1120. What are the measure of its base
angles?​

Answer 1

Let ΔABC be an isosceles triangle with vertical angle ∠A=100∘ and AB=AC.

Then,

AB=AC⇒∠B=∠C

But, ∠A+∠B+∠C=180∘

∴100∘+2∠B=180∘⇒∠B=40∘

Hope's it helps you