In ΔABC, AB = AC. If ∠A is twice the sum of other two angles of the triangles, then the measure of $\frac{1}{2}$ ∠A is :

60°

If the two sides of a triangle is equal then it will be a isoceles triangle.

We have,

In ΔABC, AB = AC. If ∠A is twice the sum of other two angles.

So, the sum of angles of a triangle = 180^o

Let the value of ∠A = 2x

then the value of other two angles will be = x

So, 2x + x = 180

x = 60

and ∠A = 12x = 120^o

So, the value of $\frac{1}{2}$  × ∠A = $\frac{1}{2}$ × 120 = 60^o