Chapter 1 - Equations and Inequalities - 1.5 Applications and Modeling with Quadratic Equations - 1.5 Exercises - Page 132: 39

$16.4$ft

We can use the Pythagorean theorem to find the length of the ladder $a^2+b^2=c^2$ where $a$ is the ground from the ladder to the wall, $b$ is the wall height to the window, and $c$ is the length of the ladder. $(8+2)^2+(9+4)^2=c^2$ $10^2+13^2=c^2$ $100+169=c^2$ $269=c^2$ $\sqrt{269}=c$ Rounded to a tenth of a foot, the ladder should be $16.4$ft long