What is the area of a regular 30-gon with a radius of 20 feet? Round your anwer to the nearest tenth, if necessary

This polygon is comprised of 30 congruent triangles, each with a central angle of 12°  

And using trig, each has an area of......

(1/2)(20)^2 sin(12°) = 41.5823381636 sq ft

So, 30 times this = 1247.470144908 sq ft  = 1247.5 sq ft  (rounded to the nearest tenth)