We took a brief look at frustums in class. A frustum is a cone with the top sliced off, like a rolo. To find the volume of a frustum, find the volume of the original cone and subtract the volume of the cone that has been removed from the top. Sometimes you aren't given the height of the original cone but you can figure it out by thinking about similar shapes.
In class we did some A* GCSE questions – here they are with answers - well done if you understand these.