Idon't know how to solve this question 19?

This isn't the answerrr bu I believe the answers for the odd #'s are in the back of the book!. But find the area of the square. Then find the area of the circle. Then subtract the square from the circle.

So just like the other answer said, to look for the squares area you'll need to multiply 8.5 times 8.5 to get 72.25. Theeen, take that radius that they give you and plug it into your formula for area of a circle; pi•r^2.
That gives you 113.09.
Subtract both of those numbers to get 40.84!
Ooo i hope that's right.
Hope this helps : D