Question

please tell this question no. 31

Answer 1

Solution:

Given:In an Isosceles triangle.,the base angles are equal.
The vertex angle is twice of each base angle.

To find: The measures of the triangle.

As we know that, Isosceles triangle triangle have 2 sides and angles equal,.
let the equal angles be x,.
The third angle is twice the base angles (equal angles {namely∠B and ∠C}), 
         A
        / \
      /     \
    /  2x  \               
  / x        x\              
/-------------\
B               C
sum of the 3 angles of a triangle equals 180°

x+2x+x=180°
        4x=180°
          x=45°
∴The equal angles (∠B and ∠C)=45°
∴ ∠A(vertex angle)=2x=2(45°)=90°

                       Hope it Helps!!