Question

A can of paint will cover 400 square feet. What is the length of the edge of the largest square that can be painted with this can of paint?

Answer 1

For the area of a circle is πr² as you stated so all you do is set 400 equal to πr² and solve for r.

400=πr²/π
127.32=r²
√127.32)= r
r=11.3

Same thing for this except you use 800 instead of 400 so.

800=πr²
254.64=r²
√254.64)= r
r=15.9 or 16.0 for rounding purposes.