Quandaries
and Queries 

Hi, I need to find out how much sand I would need to order for the base of a horse round pen. The pen is 40 ft across and I would like a depth of 4 inches. I have to order the sand in cubic yards. I am a female senior citizen and I don't have a clue how to figure it. Please help! Thanks so much.... Renee 

Hi Renee, You have a circular slab of sand with a radius of 20 feet and a thickness of 4 inches. The volume of a circular slab is
where r is the radius and t is the thickness. Since you want the volume in cubic yards I would first convert all the measurements to yards. There are 3 feet in a yard so 20 feet is ^{20}/_{3} yards. 4 inches is onethird of a foot so 4 inches is
Thus the volume is
Penny 

