Students will learn what the vertical angles theorem is, how to prove it, and how to use it. Before attempting to understand the proof, students should know what linear pairs are. Some of the problems will require solving multi-step equations.

Watch these Khan Academy videos:

Vertical angles by Khan Academy

Next, give your students these challenges:

- Through the Window by NRICH
- 2019 Math Kangaroo Levels 3-4 Problem #19 by STEM4all
- Fencing Lambs by NRICH

Conclude by leading this investigation:

Bracket – Number Trivia Game

by MathPickle