Answer
$$\theta = 2.8 \space rad. \approx 160 ^o$$
Work Step by Step
Equation: $$\theta = \frac{s}{r}$$
s = length of arc = 7 cm
r = radius = 2.5 cm
$$\theta = \frac{7 \space cm}{2.5 \space cm} = 2.8$$
This result is in radians. In order to convert radians to degrees, we multiply it by $\frac{180}{\pi}$.
$angle(degrees) = 2.8 \times \frac{180}{\pi} \approx 160 ^o$
