Pythagoras with squares

Aim

To show that in a right-angled triangle a² + b² = c².

Apparatus

• Squared paper
• Ruler
• Set square

Method

1. Draw a right-angled triangle with short sides a and b.
2. Draw squares on sides a and b and count their little squares: a² and b².
3. Measure the hypotenuse c.
4. Compare a² + b² with c².
5. Repeat for at least 4 triangles.

Conclusion

a² + b² and c² agree within measuring error for every triangle. This is Pythagoras’ theorem: c² = a² + b².