Find the area of the regular 24-gon with radius 8 mm

I'm assuming you mean the polygon CIRCUMRADIUS
Polygon Area = (radius^2 * n) * sin (360 / n) / 2
Polygon Area = [8^2 * 24] * [sin (360 / 24) / 2]
Polygon Area = 1,536 * sin(15) / 2
Polygon Area = 1,536 * 0.25882 / 2
Polygon Area = 1,536 * 0.12941
Polygon Area = 198.77376 square mm
 

Here’s the answer. you’re supposed to use 2900 times the interest rate and then add your original amount of money. now you get 2997.15