Find the radius of a circle on which a central angle measuring [tex]\frac{5 \pi}{6}[/tex] radians intercepts an arc on the circle with a length of [tex]35 \pi[/tex] centimeters.

A. 61 cm
B. 44 cm
C. 37 cm
D. 42 cm



Answer :

To find the radius of a circle where a central angle measuring [tex]\(\frac{5 \pi}{6}\)[/tex] radians intercepts an arc of length [tex]\(35 \pi\)[/tex] centimeters, we can use the relationship between arc length ([tex]\(s\)[/tex]), radius ([tex]\(r\)[/tex]), and the central angle ([tex]\(\theta\)[/tex]) in radians. The formula for the arc length is:

[tex]\[ s = r \theta \][/tex]

Given:
- [tex]\(s = 35 \pi \)[/tex] centimeters
- [tex]\(\theta = \frac{5 \pi}{6}\)[/tex] radians

We need to isolate [tex]\(r\)[/tex] in the formula [tex]\(s = r \theta\)[/tex]. Doing this involves solving for [tex]\(r\)[/tex]:

[tex]\[ r = \frac{s}{\theta} \][/tex]

Substitute the given values for [tex]\(s\)[/tex] and [tex]\(\theta\)[/tex]:

[tex]\[ r = \frac{35 \pi}{\frac{5 \pi}{6}} \][/tex]

To simplify the expression, divide by the fraction [tex]\(\frac{5 \pi}{6}\)[/tex]:

[tex]\[ r = 35 \pi \times \frac{6}{5 \pi} \][/tex]

Notice that [tex]\(\pi\)[/tex] in the numerator and denominator cancel out:

[tex]\[ r = 35 \times \frac{6}{5} \][/tex]

Now, multiply:

[tex]\[ r = \frac{35 \times 6}{5} \][/tex]

[tex]\[ r = \frac{210}{5} \][/tex]

[tex]\[ r = 42 \][/tex]

Thus, the radius of the circle is [tex]\(42\)[/tex] centimeters.

The answer is [tex]\( \boxed{42} \)[/tex].