A. If the third side is the longest side, then we're looking for the hypotenuse. By definition of Pythagorean Theorem:
The square of hypotenuse is equal to the sum of the squares of the two shorter legs/sides.
Then, with c as the hypotenuse
c² = 10² + 6²
c² = 100 + 36
[tex] \sqrt{c ^{2} } = \sqrt{136} [/tex]
[tex]c = \sqrt{(4)(34)} [/tex]
[tex]c = 2 \sqrt{34} inches[/tex]
B. If the third side is a shorter leg, then, with b as the shorter side, and c ans the hypotenuse, then:
b² = c² - a²
b² = 10² - 6²
[tex] \sqrt{ b^{2} } = \sqrt{100-64} [/tex]
[tex]b = \sqrt{64} [/tex]
b = 8 inches