The other person provided a great answer but i do it a little different....
[tex]\left[\begin{array}{ccc}A^2=C^2-B^2\\A^2=10^2-6^2\\A^2=100-36\\A^2=64\\\sqrt{64}=8 \end{array}\right][/tex]
All i did was use the formula A^2=C^2-B^2. I Plugged in the numbers to the formula and got A^2=10^2-6^2. Next, I found what 10^2 equals by doing 10*10 which equals 100. Then, i found out what 6^2 equals by doing 6*6 which equals 36. Next, what i did was subtracted 100 from 36 and got 64. Finally i found the square root of the number 64 which equal 8 since 8x8=64.
