math
posted by Sam on .
carpet is $25 per square yard. what is cost of circulare rug 9ft in diameter?

A = pi * r^2
A = 3.14 * 1.5^2
A = 2.25 sq. yards
25 * 2.25 = $______ cost 
The formaula works for a rectangle, but this is a circle. How do you convert sides of a circle? The answer is $176.63, but I can't "make it fit".

25 * pi * 2.25 = 176.71
close enough to me. (Ms Sue dropped the pi on line 3. A typo you could have caught on careful reading and math checking!) 
Thank you so much.