Answer:
The hypotenuse is about 13.892 feet
The entire length is about 32.892 feet
Explanation:
First, we have to use the Pythagorean Theorem to find the hypotenuse. The Pythagorean Theorem is:

Plug in the values...

Simplify the exponents...
49 + 144 =

Now we add.
193 =

To remove the exponent from c, lets take the square root of it.

Which is almost 13.892 feet.
Now to find the perimeter of the entire triangle, lets add up all of the sides.
12 + 7 + 13.892 is roughly 32.892 feet. Hope this helps you!