## Elementary Geometry for College Students (6th Edition)

9$\pi$ cm
CD is the minor arc of the circle We need to find out the length of CD In a circle whose circumference is c, the length l of an arc whose degree measure is m is given by l =$\frac{m}{360}$ * c Therefore for given circle c = 2$\pi$ r = 2$\pi$ * 12 = 24$\pi$ cm given m =135$^{\circ}$ Therefore lCD = $\frac{m}{360}$ * c = $\frac{135}{360}$ * 24$\pi$ =9$\pi$ cm