math
posted by syram on .
A circular coaster, with a diameter of 7 inches, is positioned on a white placement. The placement is a circle whose radius is equal to the diameter of the coaster. About how many square inches of the placemat are NOT covered by the coaster? Show your work.

It would help if you proofread your questions before you posted them.
I assume that all of your "placements" are really placemats.
Area = π * r^2
d = 2r
Area of coaster = π * 3.5^2
Area of placemat = π * 7^2
Subtract area of coaster from area of placemat.