Volume of pyramids

Find the volume of a pyramid with a base that is 12 meters by 6 meters and a height of 7 meters.

A pyramid with a rectangular base has a volume of 480 cubic inches and a height of 10 inches. The width of the rectangular base is 9 inches. Find the length of the rectangular base.

If this is the base of a pyramid with a volume of 198 cubic yards, what is the height of the pyramid?

There is a large pyramid standing 12 ft tall with a volume of 256 cubic feet. Beside it is a small pyramid, that is similar, with a volume of 4 cubic feet. What is the height of the small pyramid?

You are a member of a club that is building a float for a parade at the top of the float there's going to be a small pyramid. The base needs to be a three foot square and it needs to be four feet tall. The options you have a Styrofoam, wood, or plaster. The weight per cubic foot of each is listed below. Styrofoam 3 pounds per cubic foot Wood 47 pounds per cubic foot Plaster 53 pounds per cubic foot Plaster is very durable and easy to decorate Wood is fairly durable but time consuming to decorate Foam is easy to decorate but very fragile What would each pyramid weigh? Which material would you choose and why?