### Home > INT2 > Chapter 9 > Lesson 9.3.2 > Problem9-100

9-100.

The area of a sector of a circle is given by the equation $A = \frac { \theta } { 360 } ( \pi r ^ { 2 } )$where r is the radius of the circle and $θ$ is the measure in degrees of the arc of the sector.

1. Solve the equation for $θ$.

$A = \frac{\theta}{360}\pi r^2$

$360(A) = 360(\frac{\theta}{360} \pi r^2)$

$360A = \theta \pi r^2$

$\frac{360A}{\pi r^2} = \frac{\theta \pi r^2}{\pi r^2}$

$\frac{360A}{\pi r^2} = \theta$

2. Solve the equation for $r$.

Use the same procedures as in part (a) but additional square rooting is needed.