Use the Pythagorean theorem.
\(a^2+b^2=c^2\)
it doesn't matter which value is which since we are looking for the hypotenuse, so we would plug in given values:
\(6^2+8^2=c^2\)
From here we do the math to solve for c
\(36+64=c^2\)
\(100=c^2\)
\(\sqrt{100} = \sqrt{c^2}\)
Final answer ----> C=10