Lesson objective: Find the volume of regular pyramids with rectangular and triangular bases.

This lesson helps to build skill with finding volumes of pyramids. Images of three-dimensional figures are used here because they support understanding the properties of a three-dimensional figure from a two-dimensional image. This work develops students' understanding that volume of a three-dimensional figure is always a measure of the amount of space taken up by the figure.

Students engage in Mathematical Practice 7: Look for and make use of structure as they learn the importance of the relationship between a pyramid and a rectangular prism of the same height, to find the volume of the pyramid.

**Key vocabulary:**

- base
- face
- prism
- pyramid
- slant height
- vertical height
- volume