Question

A regular pentagon is created using the bases of five congruent isosceles triangles, joined at a common vertex. The total number of degrees in the center is 360°. If all five vertex angles meeting at the center are congruent, what is the measure of a base angle of one of the triangles? 54° 72° 108° 144°

Answer 1

It’s actually A: 54

Answer 2

B.
`72^(o)`

Explanation:

An isosceles triangle has two equal sides and angles (called base angles).

From the question, the common vertex of 5 congruent isosceles triangles are joined. Thus, creating a regular pentagon which has five sides.

Given that the five congruent triangles form a total of 360° at the center, then;

the measure of a base angle of one of the triangles =
`(360^(o) )/(5)`

=
`72^(o)`