First, students will review the formula for the diagonal length of a rectangle. After that, students will learn how to use the Pythagorean theorem to find the length of an internal diagonal of a rectangular prism. Here's a problem where the rectangular prism is a cube. Here's a problem where both the right triangles within the rectangular prism are Pythagorean. Next, give your students this challenge. Finally, give them this one.

Conclude by giving your students these challenges:

- 2020 Math Kangaroo Levels 1-2 Problem #18 by STEM4all
- Hello Again by NRICH
- Six Times Five by NRICH
- Dissect by NRICH
- What Numbers Can We Make Now? by NRICH
- Jumping Checkers by Pierce School: Problem / Solution