### Home > CCG > Chapter 7 > Lesson 7.2.1 > Problem 7-55

7-55.

Jamal used a hinged mirror to create a regular polygon like you did in Lesson 7.1.4.

If his hinged mirror formed a

angle and the core region in front of the mirror was isosceles, how many sides did his polygon have? Use the formula:

Now Jamal has decided to create a regular polygon with

sides, called a nonagon. If his core region is again isosceles, what angle is formed by his mirror? Use the formula given in hint (a) and solve for the unknown piece.