I have a pentagon with side length 7, and I need to know the area. Any help?
area of pentagon = 10 * area of third triangle
area of third triangle = (1/2) * base * height
area of third triangle = (1/2) * 3.5 * (3.5 / tan 36º)
area of third triangle = 6.125 / tan 36º
area of pentagon = 10 * 6.125 / tan 36º
area of pentagon = 61.25 / tan 36º
area of pentagon ≈ 84.303 square units
*edit*
as long as this is a regular pentagon! :)
area of pentagon = 10 * area of third triangle
area of third triangle = (1/2) * base * height
area of third triangle = (1/2) * 3.5 * (3.5 / tan 36º)
area of third triangle = 6.125 / tan 36º
area of pentagon = 10 * 6.125 / tan 36º
area of pentagon = 61.25 / tan 36º
area of pentagon ≈ 84.303 square units
*edit*
as long as this is a regular pentagon! :)