Find the length of a square whose diagonal is 15cm

Arectangular prism is 3 meters long, 6 meters wide, and has a height of 9 meters. what is its surface area?

Write a recursive sequence that represents the sequence defined by the following explicit formula:

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?