With Pythagoras theorem we can find the lengths of a side in a right angled triangle given the other two sides.

With the sides of the triangle as labelled above, we use the formula
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For example

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It is important to label the sides of the triangle a, b and c in the way shown above. If you remember that c is the longest side then labelling becomes easier. Then you must use these values in their correct position in the equation![]()

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