Geometry
# Regular Polygons

What is the area of a regular hexagon with side length 2?

What is the area of a regular octagon with side length 5?

Use $\tan22.5^\circ\approx0.4,\tan67.5^\circ\approx2.4.$

Find the area of a regular decagon whose distance from its center to a vertex is 10.

Use $\sin18^\circ\approx0.3, \cos18^\circ\approx0.95.$