Question:
The vertical angle of an isosceles triangle is (10)0°. Find its base angles.
Solution:
Consider an isosceles ΔABC such that AB = AC
Given that vertical angle A is (10)0°
To find the base angles
Since ΔABC is isosceles
∠B = ∠C [Angles opposite to equal sides are equal]
And also,
Sum of interior angles of a triangle = 180°
∠A + ∠B + ∠C = 180°
(10)0° + ∠B ∠B = 180°
2∠B = 180∘ - (10)0°
∠B = 40°
∠B = ∠C = 40°