# Math Help - Central angle of circle

1. ## Central angle of circle

Find the central angle of a circle with a radius of 3.2 cm, which subtends an arc 17 cm long.

Thanks for any help!

2. This question completely hinges on knowing the formula $S=r\theta$ where S is the arc length, r is the radius of the circle, and $\theta$ is the measure of the central angle of the circle in radians (NOT DEGREES)

So, we have S and r, and we need to find $\theta$

$17=3.2*\theta$ so $\theta=\frac{17}{3.2}=5.3125$ if you want $\theta$ in degrees, multiply 5.3125 by $\frac{180}{\pi}$