3. at a zoo, the lion pen has a ring-shaped sidewalk around it. the outer edge of the sidewalk is a circle with a radius of 11 m. the inner edge of the sidewalk is a circle with a radius of 9 m. (a) write and simplify an expression or equation for the exact area of the sidewalk. (b) find the approximate area of the sidewalk. use 3.14 to approximate π.

121pi - 81pi or 125.6 square meters

To find this answer, imagine that you have one circle inside of another.  The area between the two circles forms a ring around the outside. To find this area, subtract the larger circle from the smaller circle.

Since the area of a circle is pi x r ^2, the area is:
pi x 11^2 minus pi x 9^2
Or
121 pi minus 81 pi

If you sub in 3.14, you will get an approximate area of 125.6.

For the first question the answer is a, for the second c, for the third d, for the 4th b, for the 5th a