Question

If a circular arc of the given length s subtends the central angle theta on a circle, find the radius of the circle. s=10cm, theta=4

Answer 1

\[s=r \theta
... so...
r=\frac{ s }{ \theta} \]

Answer 2

the previous equation is for angle theta in radians

Answer 3

if it is in degrees then:
\[s=2\pi r(\frac{ \theta }{ 360 })\]

Answer 4

so:
\[r=\frac{ s }{ 2\pi (\frac{ \Theta }{ 360 }) }\]