Here are the solutions to the questions. Question 31: The length of an arc of a circle is given by the formula $L = \frac{\theta}{360^\circ} \times 2\pi r$, where $\theta$ is the angle subtended at the center in degrees, and $r$ is the radius. Step 1: Convert the given values to fractions. Given arc length $L = 1 \frac{19}{36} \text{ cm} = \frac{36 \times 1 + 19}{36} \text{ cm} = \frac{55}{36} \text{ cm}$. Given radius $r = 3.5 \text{ cm}