# Volumes

Formulas…formulas….formulas….

Volume Of A Cuboid

Simple! A cuboid is just a regular block. The volume is just length times height times width!

Volume Of A Prism

A prism is just a 3D shape with the same shape all the way through.

Volume = area of cross-section shape x length

A cylinder is a prism that has a circle as its cross sectional shape. So for a cylinder:

Volume = hπr2 Volume Of A Sphere

Volume of a sphere = 4/3 πr3 If asked to find the volume of a hemisphere, i.e. half a sphere, work out the volume for the whole sphere then divide by two. You can use the same method if you get a surface area question about a hemisphere.

Volume Of A Pyramid

A pyramid has a flat base (which can be a triangle, a square etc) but meets at a point at the top.

Volume = 1/3 x base area x vertical height Volume Of A Cone

A cone is a pyramid with a circular base. Therefore:

Volume = 1/3 x  πr2 x height Volume Of A Frustum

A frustum is a cone with its pointy bit cut off. To work out the volume just find the volume of the full cone and subtract the volume of the cut off cone. 