Question 172551
 a=3, b=4, c=?
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Assuming a and b are the short sides of a right triangle:
{{{c^2 = a^2 + b^2}}}
{{{c^2 = 9 + 16}}}
{{{c^2 = 25}}}
c = 5
This is the 3, 4, 5 right triangle that we see a lot of.
Carpenters use this to see if 2 walls are at a right angle: they measure 3' from the corner on one wall, 4' on the other, and check to see if the diagonal is 5 feet.