Activity 05

Overview

Explore 90-60-30 triangle and used that to fold an equilateral triangle.

Establish that 90-60-30 triangle always has a ratio of $\frac{1}{2}$ and 90-45-45 triangle always has ratio of $\frac{1}{\sqrt{2}}$. Use that to briefly introduce sine and cosine.

Use the established fact that a 90-60-30 triangle has a ratio of $\frac{1}{2}$, to fold an equilateral triangle on a square sheet of paper.

Origami Model

Hexaflexagon

Notes

There were three parts in this activity.

1. Solving the worksheet to establish the properties of 90-60-30 triangles
2. Folding an equilateral triangle on a square sheet of paper
3. Hexaflexagons

Last line!