Question

A 20 foot ladder is leaning against a house. The bottom of the ladder is 3ft from the house. To the nearest tenth of a foot, about how high does the top of the ladder reach ?

Answer 1

Let's draw a rough sketch:

We have a 20 foot ladder that is leaning against a house, height h.

The base of the ladder is 3 feet from the base of the house.

We need to find h.

We can use the pythagorean theorem to find h. So,

$\begin{gathered} 3^2+h^2=20^2 \\ 9+h^2=400 \\ h^2=400-9 \\ h^2=391 \\ h=\sqrt[]{391} \\ h\approx19.8 \end{gathered}$