The arc of a circle, radius $13$13 cm, subtends an angle of $\theta$θ radians at the center of the circle, and measures $11.7$11.7 cm in length. Solve for $\theta$θ, the angle subtended at the center.
Write each line of working as an equation.
A sector of a circle, radius $2$2cm, has an arc length of $3.9$3.9cm. Find the angle $\theta$θ formed at the center of the circle in radians, correct to two decimal places.
A sector of a circle, radius $95$95mm, has an arc length of $159$159mm.
Find, in radians, the angle of smallest positive measure that is coterminal with an angle of $\frac{9\pi}{4}$9π4.