Download Presentation
## Pythagoras

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**History**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.**Pythagoras came up with a rule to work out the sides of a**right angled triangle. The rule only works for right angled triangles. To use the rule you need 2 sides.**The rule says that if you square each of the two short sides**of a triangle then add them together it will equal the square of the long side. Short Long Short**c**a b a2 + b2 = c2**long**short short short2 + short2 = long2**To find the long side**• Square both short sides • Add the squares together • Square-root your answer**3 x**4 32 = 9 42 = 16 16 + 9 = 25 Square root of 25 = 5**9 x**12 92= 81 122= 144 81 + 144 = 225 Square root of 225 = 15**To find a short side**• Square the long side • Square the short side • Subtract the short square from the long square • Square-root your answer**a 20**16 202 = 400 162 = 256 400 - 256 = 144 Square root of 144 = 12**a 14**11 142= 196 112= 121 196- 121 = 75 Square root of 75 = 8.7 (1dp)**Recap (don’t copy)**• Pythagoras's rule can be used to find the last side of a right angled triangle. • The first step is to square the sides. • Then: • if they are both short sides add them. • or take the short side away from the long. • Then square root your answer.**4.5 x**6 4.52 = 20.25 62 = 36 20.25 + 36 = 56.25 Square root of 56.25 = 7.5