The side lengths of a right triangle are
; 
Apply Pythagorean theorem: 
(Substitute 6 for a and 10 for c)
(Evaluate powers:
)
(Subtract 36 from each side)
(Additive inverse property:
)
(Additive identity property:
)
(Subtract:
)
(Take square root to each side)
(Write
)
(Cancel square and root)
The unknown length of
in.