I need help understanding how to convert my standard cereal boxs measurements into a cylinder ? my standard cereal box has a length of 9 inches , height 12 inches and width of 3 inches , the surface area is 342 inch^2 and a volume of 324 inch^2 , my issue is im trying to find a volume for my cylinder that is the same as my standard boxs or higher but my surface area needs to be less than the standards. I am trying to find the volume for my cylinder that works but i need to understand how I find the r? pi(r^2)(12)=324 , this equation is suppose to help me find the radius and then help me find the volume but I dont understand what i need to do first?