### Home > INT2 > Chapter 8 > Lesson 8.2.2 > Problem8-47

8-47.

Always a romantic, Marris decides to bake his girlfriend a cookie in the shape of a regular dodecagon ($12$‑gon) for their $12$-day anniversary.

1. If the edge of the dodecagon is $6$ cm, what is the area of the top of the cookie?

2. His girlfriend decides to divide the cookie into $12$ congruent pieces.
After nine of the pieces have been eaten, what area of the cookie is left?

Try splitting the cookie into triangles.
What information do you already know about these triangles' angles and sides?
Can you use this to find the area of a single triangle?

Multiply the area of a single triangle by the number of triangles remaining after some have been eaten.