posted by dani .
a 15 ft ladder is palced against a wall such that its base is 9 ft away from the wall. if the base of the ladder is moved to 6 ft away from the wall, by about how much will the top of the ladder move up the wall?
at 9 ft, you have a 9-12-15 triangle.
at 6 ft, the ladder reaches to height h, where
6^2 + h^2 = 15^2
h = 13.75 ft
so, the ladder has moved up 1.75 ft