I think its 672 because * hrs a day is 56 and when you multiply that by 12 its 672<span />
Are you supposed to estimate or get an exact answer? If you're estimating you can see if the number is close to any perfect squares. In this case 63 is very close to 64, and 48 is very close to 49. The answers can then be estimated to be approximately 8 and 7, respectively.
The radius would be 9.55, Hope that helps
