How do you use pythagorean theorem finding c on a right triangle with one side 10 and the other 5?

The pythagorean theorem is C^2=a^2+b^2.(^2=squared) Where C is equal to the longest side of the of the triangle or the hypotnos. So if you plug 10 into a and 5 into b then your formula is C^2=10^2+5^2 simplifying to C^2=100+25 simplifying again C^2=125. Now you don't want C^2 you just want c so you have to take the square root of both sides. sqrt(c^2)=sqrt(125) simplifying to c=11.180 if you round to the 3rd decimal place. Final answer c=11.180.

Just remember: A^2 + B^2 = C^2 (^2 = squared or raised to the second). Also. A and B are either of the legs. C is 100% of the time the hypotenuse! The hypotenuse is the longest side of a triangle and will always be located directly across from the right angle symbol (the 90 degrees marker). If there is no marker, then the triangle is not a right angle triangle, and the Pythagorean Theorem cannot be used.