Question

Shannon makes large cookies. These cookies are 22 inches in diameter. How much icing will she need to cover the top of each cookie?

Answer 1

You must ice the surface, or area, of each cookie.
\[A=\pi r ^{2}\]
\[d=\ 2r\]
\[r=d/2\]
\[d=22 in\]
\[r=22in/2 = 11in\]
\[A=\pi r ^{2}\]
\[A=\pi (11in) ^{2}\]
\[A=121\pi \ in ^{2}/cookie\]