Stuck with triangle proofs? Take a 180° and provide learners with a guided worksheet that tests their knowledge with triangle inequalities. The questions require different types of proofs that range in levels of difficulty. 

How do you build a polygon from an inequality? An engaging lesson challenges pupils to do just that. Building from the previous lesson in this series, learners write systems of inequalities to model rectangles, triangles, and even...

This lesson focuses on the Triangle Inequality, when the sum of the lengths of any two sides of a triangle is greater than the length of the third. When this happens, the three sides cannot form a triangle.

Given the lengths of two sides of a triangle, what can we say about the third side? Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.