2. Pythagoras was a Greek mathematician who was born approximately 2700 years ago. He was responsible for figuring out a lot of modern maths, especially geometry and trigonometry.

3. Pythagoras is said to have come up with a rule to work out the sides of a right angled triangle. Pythagoras’ Rule The rule only works for right angled triangles.

4. The rule says that if you square (times by themselves) the two short sides of a triangle then add them together it will equal the square of the long side. Short Long 1 Short 2

5. c a b a 2 + b 2 = c 2

6. c a b short 2 + short 2 = long 2

7. 1. Square both short sides 2. Add the squares together 3. Square-root your answer

8. 3 x 4 3 2 + 4 2 = x 2 9 + 16 = 25 a = √25 = 5

9. short 2 + short 2 = long 2 rearrange short 2 = long 2 - short 2

10. 1. Square the sides 2. Subtract the short square from the long square 3. Square-root your answer

11. a 20 16 20 2 – 16 2 = a 2 400 - 256 = 144 a = √144 = 12