You can
put this solution on YOUR website!You first need to recognize that the ladder and the wall form a right triangle with the height=9 and the base=3. Since this is a right triangle, you can use the Pythagorean theorem to find the hypoteneuse (which is the length of the ladder.)
Pythagorean theorem says:

where:
c=hypoteneuse
b=one side
a=other side
So your equation is:

Simplifying...

Take the square root of both sides...

You can simplify it a little more...

Plug that into your calculator if you want a value and you are done.
Good Luck,
tutor_paul@yahoo.com