### Home > CCG > Chapter 9 > Lesson 9.2.2 > Problem9-84

9-84.

Which has greater measure: an exterior angle of an equilateral triangle or an interior angle of a regular heptagon ($7$-gon)? Show all work. Homework Help ✎

Remember that the sum of all exterior angles is equal to $360°$.

$\frac{360°}{3}=120°$for each exterior angle, since it is an equilateral triangle.

Measure of one interior angle $=\frac{(n-2)(180)}{n}$

Substitute $7$ for $n$ and determine which of the two angles has a greater measure.