Folding an Equilateral Triangle

Sixty degrees from a square

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• A fold is a reflection across the crease line.
• Folding a corner onto the centre line through the opposite corner makes a 60° angle.
• This gives an equilateral triangle from a square.

Steps

1. From square to triangle
2. Land on the centre line
3. Height of the triangle
4. Area of the triangle
5. The largest triangle
6. Why it works