What is the perimeter of a 30-gon with radius 1
3 answers
30*2*1*sin(1/2 * 360/30)
look at one of the 30 central triangles.
Each will be isosceles with a vertex angle of 12°
base^2 = 1^2 + 1^2 - 2(1)(1)cos12°
= 2 - 2cos12°
so the perimeter is 30(2 - 2cos12°)
= 60 - 60cos12°
use your calculator if you need a decimal answer.
Each will be isosceles with a vertex angle of 12°
base^2 = 1^2 + 1^2 - 2(1)(1)cos12°
= 2 - 2cos12°
so the perimeter is 30(2 - 2cos12°)
= 60 - 60cos12°
use your calculator if you need a decimal answer.
I messed up, forgot to take the square root of 2-2cos12° for the base of the triangle
perimeter = 30√(2-2cos12) = same answer as oobleck
perimeter = 30√(2-2cos12) = same answer as oobleck