Quandaries
and Queries 

HI  I seem to be having a grey matter moment. I have a pond that I need to treat with an anti algae solution which needs to applied based on the volume of water in the pond (in gallons). The rough diameter of the surface of the pond = 25 ft The depth of the pond = 8 ft The pond shape is conical How many gallons of water are in my pond? I'm sure I could have solved this simple equation 35 years ago in when I was in High School, but somehow ... not today. I appreciate your assistance in this matter. Douglas 

Hi Douglas, I drew a diagram of what I think your pool looks like.
The volume of a cone is
where r is the radius of the circular base and h is the height. Your pool has a height of 8 feet and the base of radius 12.5 ft so the volume is
I know that there are 231 cubic inches in an American gallon so I need to convert the volume above from cubic feet to cubic inches. There are 12 inches in a foot so there are 12^{3} cubic inches in a cubic foot. Hence the volume of your pool is
Thus, converting to gallons, the volume is
Penny 

