## Geometry: Common Core (15th Edition)

a) perimeter=$56.5\ in$; area=$254.5\ in^2$ b) perimeter=$22.9\ m$; area=$41.9\ m^2$
a) Use the formula for circumference and substitute the given radius(r). $C=2\pi r=2\pi\times9=18\pi=56.5$ Use the formula for area and substitute the given radius(r). $A=\pi r^2=\pi(9)^2=81\pi=254.5$ b) The radius of a circle is half the diameter, so the given radius is 3.65 m. Use the formula for circumference and substitute the given diameter(d). $C=\pi d=7.3\pi=22.9$ Use the formula for area and substitute the given radius(r). $A=\pi r^2=\pi(3.65)^2=13.3225\pi=41.9$