Question

Find the area of a regular decagon with radius 7 cm. Round to the nearest tenth. Please help

Answer 1

144 cm squared

Explanation:

The steps are same as for the calculation of area of the octagon I solved for you earlier. That is why I will post here only calculations and not the actual steps.

360/10=36 degrees

36/2=18 degrees

sin(18)=x/7

x= 2.1631 cm

Cos(18)=y/7

y=6.6573

y*x= 14.4006

14.4006*10=144 cm squared