Question

The figure shows a triangle with 2 congruent sides. The angle between the congruent sides measures x degrees and a different angle measures 70 degrees. The angles opposite the congruent sides of an isosceles triangle are congruent. Find the value of x in the triangle.

Answer 1

• 40°

Explanation:

Since the triangle is isosceles and the angle between the congruent sides is x, the other two angles measure the same value.

Sum of the interior angles is 180°:

• x + 2*70° = 180°
• x + 140° = 180°
• x = 40°