use the pythagorean theorem

All I did was use the formula A^2+B^2=C^2, then I plugged in the given number giving me 8^2+6^2=C^2. Next, I Found what 8^2 equals by doing 8*8 which equals 64. Then, i found out what 6^2 equals by doing 6*6 which equals 36. Next, i added 64 and 36 together and got 100. I then found the square root of 100 and got 10 since 10*10 = 100. In the first one i just added km to the formula and numbers. What the other guy did was the following...
[tex]\left[\begin{array}{ccc}A^2+B^2=C^2\\8^2+6^2=C^2\\64+36=100\end{array}\right][/tex]
What he did wrong was; he didn't find the square root of 100 which is 10 so he provided the wrong answer as 100km. Remember when using The Pythagorean Theorem you must find the square root of the final number unless your answer choices look like this --> [tex]\sqrt{x}[/tex] If it is all the square root of the number do not find the square root of the number and just choose the correct answer choice. In this case if it were to be all square root answer choices your answer choice would be [tex]\sqrt{100}[/tex].
Hope this helps!