Question

A regular dodecagon is inscribed in a circle of radius 24 units.Find the perimeter of the regular dodecagon.

Answer 1

finally :)

Answer 2

Since 20 sides are present the angle is 2pi/20.
Now use cosine rule.\[a ^{2} = b ^{2}+c ^{2}-2ab \cos A\]
You have the length of one side of the poloygon.
Multiply by 20 to get the perimeter.