Question

The ratio between the vertical angle and a base angle of an isosceles triangle is 4:3,find all the angles of the triangle

Answer 1

Given ratio between the base angle and vertical angle of an isosceles traingle is 2:5

⇒ base angle / vertical angle = 2 / 5

let base angle = x

⇒ verticle angle = (5/2)x

we know that
verticle angle + base angle + base angle = 180°

⇒ ( 5/2 + 1 + 1 ) x = 180°

⇒ (9/2)x = 180°

⇒ x =  ( 180° x 2) / 9

⇒ x = 40°

verticle angle = (5/2) x 40° = 100°