The length of
, hypotenuse
, and length b = ?.
Apply pythagorean theorem:
.
(Substitute
, and
)
Evaluate square roots:
.

Apply subtraction property of equality: a = b then
.
(Subtract 31 from each side)
Apply commutative property of addition: a + b = b + a.
\
(Apply additive inverse property:
)
(Subtract:
)
Apply square roots property:
then
.

The positive value of
.
The length of
.