standard_description: Prove theorems about triangles. Theorems include: a line parallel to one side of a triangle divides the other two proportionally, and conversely; the Pythagorean Theorem proved using triangle similarity.
problem_activity: Stage 1: Objects
Required Preparation
Materials to Gather
Connecting cubes
Materials to Copy
Blackline Masters
Number Mat 1–5

Narrative
One partner builds a tower with 5–10 cubes. The other partner rolls a cube onto the number mat to figure out how many cubes to subtract. Students work together to figure out how many cubes are left.


aligns: no