80% of what number is 64

Anew fountain in the shape of a hexagon will have 6 sides of equal length. on a scale drawing, the coordinates of the vertices of the fountain are: (7.5,5), (11.5,2), (7.5,−1), (2.5,−1), (−1.5,2), and (2.5,5). how long is each side of the fountain?

Acylinder has volume 45π and radius 3. what is it’s height?

At the beginning of 1974/75,2 years a man invested #2000 in a bank at 12.5% compound interest, if it degree #650 at the end of each two years to pay his son's school fees, after payment of interest to pay his son's school fees, how much did he have left at the beginning of the 1978/79 school year?