​In an isosceles ∆ABC, if the measure of ∠A is twice that of the base ∠B, then the measure of ∠C will be: ​

Correct option is A

Given:

​In an isosceles ∆ABC, if the measure of ∠A is twice that of the base ∠B. 

Concept Used: ​

In an isosceles triangle, the angles opposite the equal sides are also equal.

Solution:

Let ∠B = x
Since ∠A is twice ∠B, then,

∠A = 2x

∠B = ∠C

x = x

​The sum of the angles in any triangle is always $$180^∘$$​.

∠A + ∠B + ∠C = 180°

2x + x + x = 180°​

4x = 180°

x = $$\frac{180°}{4}$$

x = 45°

∠C in the isosceles triangle is 45°

Thus, option (a) is correct.