## Geometry: Common Core (15th Edition)

$6.25\pi$
Use the distance formula to find the diameter. $d=\sqrt{(5-2)^2+(5-1)^2}$ $d=\sqrt{(3)^2+(4)^2}$ $d=\sqrt{9+16}$ $d=\sqrt{25}$ $d=5$ The radius(r) is half the diameter, so r=2.5. Use the formula for the area of a circle. $A=\pi r^2=\pi (2.5)^2=\pi (6.25)=6.25\pi$