Question

Use the arc length formula and the given information to find r.

s = 12 cm, θ = 36°; r = ?

thirty divided by pi cm
sixty divided by pi cm
one third cm
one hundred twenty divided by pi cm

Answer 1

Explanation:

The thing with the arc length formula, s = rt, is that t is the angle in radians. Ours is in degrees, so we have to change it:

36 ×
`(\pi )/(180)=(\pi )/(5)`

So the formula we use to solve for r is:

`12=(\pi )/(5)r`

Multiply both sides by 5 over pi to get that

`r=(60)/(\pi ) cm`