Question

1. A metal washer 1 inch in diameter is pierced by a 1/2 inch hole. What is the volume of the washer if it is 1/8 inch thick?

2. How many square feet of aluminum materials will be needed in order to construct an open top right cylindrical tank which is 6ft high and has a diameter of 2ft, if only 5% of the total surface of the cylinder is to be allowed for the waste.

Answer 1

1. pi * thickness * (R_washer^2-R_hole^2).

2. Don't understand this.