## Precalculus (6th Edition) Blitzer

$\frac{9}{4}$ radians
The measure of the central angle θ = $\frac{length of the intercept arc}{radius}=\frac{s}{r}.$ s = 18 yards, r = 8 yards. θ = $\frac{s}{r}$ = $\frac{18}{8}$ = $\frac{9}{4}$ radians.