\( \def\dfrac#1#2{\displaystyle\frac{#1}{#2}} \def\solve#1{\begin{array}{rcl}#1\end{array} } \)

Home / 08 Trigonometric Functions / 37 Arc Length

Example: Determine the length of the arc of a circle with a radius of 6cm if the arc formed is subtended by an angle of \(234^\circ\). Give an exact answer.


Solution To answer this question we will first convert the degrees to radians:

\[ \solve{ 234\times\dfrac{\pi}{{180}}&=&\dfrac{234\pi}{{180}}\\&=&\dfrac{13\pi}{{10}} } \]

Next, we will use the arc length formula, \(s=r\theta\), to calculate the exact length.

\[ \solve{ s&=&6\times\dfrac{13\pi}{{10}}\\ s&=&\dfrac{39\pi}{{5}}\text{ cm} } \]

And now we have our exact answer for the length of the arc subtended by the angle given.