Aladder reaches a window 12ft above the ground and the foot of the ladder is 4.8 from the wall. how long is the ladder

If you draw this, you'll see it forms a triangle, with the ladder as the hypotenuse. We're given the two side measurements, so we can easily use Pythagorean theorem to find the ladder length (x):
(12^2 + 4.8^2) = x^2 x = 12.92ft