



 
Hi Dannielle, You use Pythagoras theorem. The theorem says that if a right triangle has side lengths a, b and c where c is the length of the hypotenuse (the side opposite the right angle) then a^{2} + b^{2} = c^{2}. For example suppose you have sides of length a = 3 inches and b = 4 inches then by Pythagoras theorem a^{2} + b^{2} = c^{2} so 3^{2} + 4^{2} = c^{2} and thus c^{2} = 9 + 16 = 25 and hence c = √25 = 5 inches. Now try your numbers,  


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