Please help: Find the exact length of the intercepted arc of a sector subtended by the central angle 30 degrees in a circle if the area of the sector is 21 square cm.

Question

Please help:  Find the exact length of the intercepted arc of a sector subtended by the central angle 30 degrees in a circle if the area of the sector is 21 square cm.

goformit100 · Answer

ok

anonymous · Answer

To find the arc lenght, there is one information missing, do you see wich?

anonymous · Answer

no I don't

anonymous · Answer

What is it?

anonymous · Answer

|dw:1349748568618:dw|
Its x that you want to find right? Just to be sure I understood the problwem

anonymous · Answer

I don't know. I was no given a picture. just the words I typed.

anonymous · Answer

Ok lets assume that thats what you want, I'm almost sure.
the definition of radian, is the arc lenght of the circle of radius 1, to find the arc lenght of any circle, you need to multiply the arc by the radius, because if the radius is doubled, the arc is obviously doubled also. so whats missing there, if you know the angle is the radius.
Try to find it now.

anonymous · Answer

|dw:1349748834652:dw|
21 =(30/360)*pi*r^2.... solve for r. use it to find  arc length = (30/360)*2r*pi