Question

The angles opposite the congruent sides of an isosceles triangle are congruent. Find the value of x in the triangle. Show all your work.

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.

Answer 1

40

Explanation:

Angles opposite congruent sides in a triangle are congruent, so the other base angle is also 70 degrees.

This means that the interior angles are 70, 70, and x

Since the sum of the measures of the angles of a triangle is 180 degrees,

70+70+x=180

140+x=180

x=40