Using the formula: Length of arc $= \dfrac{\theta}{360} \times 2\pi r$
$2.2 = \dfrac{\theta}{360} \times 2 \times \dfrac{22}{7} \times 2.8$
$\theta = \dfrac{2.2 \times 360 \times 7}{2 \times 22 \times 2.8} = \dfrac{5544}{123.2} = 45°$
(C) 45°
Use the arc length formula from the chapter summary: $\ell = \frac{\theta}{360} \times 2\pi r$. Substitute $\ell = 2.2$ cm, $r = 2.8$ cm, $\pi = \frac{22}{7}$, and solve for $\theta$. Always use $\pi = \frac{22}{7}$ unless told otherwise.