(a) John and Stan were building a sand castle. They decided to make it into a cone shape. After some time, the diameter of the sand shaped cone was 12 in and the height was 7in. What is the exact volume of the sand cone? (Show your work. Remember you can draw a picture to help you solve the problem.) (b) The boys kept adding sand, and ten minutes later the volume of the sand cone had increased by 30%. What is the exact volume of the sand cone now? (Show your work. Remember you can draw a picture to help you solve the problem.)