Question

The circle below has center C

Answer 1

well, we know that the angle DCE is 100°, and since a circle has a total of 360°, angle DFE must be 260°, and we also know that its radius is 7.

$\textit{arc's length}\\\\ s=\cfrac{\pi \theta r}{180}~~ \begin{cases} r=radius\\ \theta =\stackrel{degrees}{angle}\\[-0.5em] \hrulefill\\ r=7\\ \theta = 260 \end{cases}\implies \begin{array}{llll} s=\cfrac{\pi (260)(7)}{180}\implies s=\cfrac{91\pi }{9} \\\\\\ ~\hfill s\approx 31.76 \end{array}$