The polygon is divided into 30 isosceles triangles, with vertex angle 360/30 = 12°
So, now you have 60 right triangles with one angle 6° and hypotenuse 9mm
So, the base of each triangle is 9sin6°, and the height is 9cos6°.
The total area is thus 60 * (1/2)(9sin6°)(9cos6°)
take a google at area of regular polygons to see how this relates to the formula
area = pa
where p is the perimeter and a is the apothem.
What is the area of a regular 30-gon with a radius of 9mm?
So far I know my interior angle is 6. That is all I can seem to figure out. Thanks!
1 answer
1 answer