<PRE><B>Question 319607</B>
If distance from ground to window is X, the ladder is (X + 1) and the distance from the wall to the ladder is 9.
So Pythagoras says, X^2 + 9^2 = (X + 1)^2
X^2 + 81 = X^2 + 2X + 1
2X = 80, X=40
So the ladder is 41 feet.
You could also use the fact that Pythagorean triples are such that the small side squared is equal to the other two sides
3^2 = 4 + 5
5^2 = 12 + 13
7^2 = 24 +25
9^2 = 40 + 41</PRE>