Question

What is the measure of the vertex angle of an isosceles triangle if one of its base angle measures 34° and it’s congruent sides each measure 15 cm

68

73

112

56

Answer 1

Let the vertex angle be x.

Base angles in the isosceles triangle are congruent.

Let the base angles be α=34°

Total sum of the inner angles in the triangle is 180°.

We can make equation

2α+x=180° => x=180-2α=180-68=112

The measure of the vertex angle is 112°

Good luck!!!