Question

In an isosceles triangle the base angles are equal the vertex angle is 40° What are the base angles of the triangle?

Answer 1

In an isosceles triangle the base angles are equal the vertex angle is 40° then base angles are 140 / 2 = 70 degree each

Answer 2

The base angles of the triangle are 70° each.

Step-by-step explanation:

We are given that in an isosceles triangle the base angles are equal and the vertex angle is 40°.

Let the $\triangle$ABC be an isosceles triangle in which vertex angle ($\angle$A) is equal to 40° and the base angles are $\angle$B and $\angle$C.

Also, we know that the angle sum property of the triangle states that the sum of all angles of the triangle is equal to 180°.

Let the base angle $\angle$B = x, then $\angle$C will also be x.

So,  $\angle$A + $\angle$B + $\angle$C = 180°

       $40\° + x+x=180\°$       {because base angles are equal}

       $2x+40\° =180\°$

       $2x =180\°-40\°$

        $2x= 140\°$

          $x= \frac{140\°}{2}$

          x = 70°

Hence, the base angles of the triangle are 70° each.