Answer:
step two added the 9 to each side :)
Answer:
volume will be equal to 5,655 ft³
Step-by-step explanation:
diameter of swimming pool = 40 ft
depth increases from east-west lines is from 2 ft to 7 ft
so the average depth of the swimming pool can be calculated by

hence average depth comes out to be 4.5 m
volume of water in the pool will be equal to the volume of the pool
volume = 
= 
= 5,654.86 ft³
volume will be equal to 5,655 ft³ approximately