Question

A ladder is leaning against a building so that the distance from the ground to the top of the ladder

is 4 feet less than the length of the ladder. Find the length of the ladder if the distance from the
bottom of the ladder to the building is 12 feet.

Answer 1

Check the picture below.

`x^2=12^2 + (x-4)^2\implies x^2=144 +\stackrel{F~O~I~L}{(x^2-8x+16)}\implies 0=144-8x+16 \\\\\\ 8x=144+16\implies 8x=160\implies x=\cfrac{160}{8}\implies \boxed{8=20}`