To find the diameter, divide the area(254.34) by pi(3.1415) and then square the quotient
That is the radius now just times that by 2 so 2 x 8.99 = 17.98
Now I have a felling the might be wanting 18 because 8.99 is so close to 9 and this is also true for 80.95. They probably want 80.95 = 81, which the square root of that is 9, which is the radius and if you times that by 2 the diameter would equal 18