CPM Homework Help : CCG Problem 11-99

Find the area of a regular decagon if the length of each side is $20$ units.

Step 1:

Find the measure of a central angle.

Step 2:

Use this to determine the height of one of the triangles.

Step 3:

Find the area of one of the triangles.

Step 4:

Find the total area.

Answer:

$3077.7\text{ units}^2$

A regular decagon, divided into 10 sectors, with the central angle, of one sector, marked.