CPM Homework Help : INT2 Problem 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.

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

Hint (a):

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?

More Help (a):

A dodecagon divided into 12 equal parts.

A dodecagon figure divided into 12 equal parts. One part has a side equal to 6 cm, two angles congruent, two sides congruent and the inside angle at the center 360 divided by 12 degrees.

Hint (b):

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