High water level is= 80 cm. Low water level is = 60 cm. The change of the water volume is V = A*(80-60) = 20A cm^3, where A is the base area, in cm^2. The volume equation is 20A = 62600 cm^3 From the equation, the base area A = = 3130 cm^2. ANSWER To find the new height of the water if extra 1565 cm^3 of water added, add to 80 cm. You will get then the new level = 80 + = 80 + 0.5 = 80.5 cm. ANSWER