The area of a circle is pir^2. First you will need to find the area of the concrete and subtract the area of the flower bed from that amount. The concrete is 3 feet wide so you will add that to 11.5 (half of the flower bed diameter) to find the radius. 14.5^2 pi is the entirety of the area. Then subtract 11.5^2 pi for the area of the concrete.
First, eliminate the lowest grade (76). Now, find the average/mean of the remaining 4 test grades. To do so, add up all the test grades, then divide them by the total number of test grades: