Question

Triangle JKL is isosceles. The measure of angle J is 72° and the measure of angle K is 36°. Which statement describes angle L?

Answer 1

The sum of the measures of the angles of a triangle is 180 deg.
m<J + m<K + m<L = 180
72 + 36 + m<L = 180
m<L = 72

Both angles J and L measure 72 deg.
Angles J and L are base angles measuring 72 deg.
Angle K is the vertex angle measuring 36 deg.

Answer 2

We know that all triangles equal 180° 

To find the missing angle we do this,

∠J + ∠K + ∠L = 180

72° + 36° + ∠L = 180   SUBSTITUTION 

108 + ∠L = 180°

180 - 108 = ∠L Property of algebra (Opposite of plus)

∠L = 72°