Thread: how to calculate the area and arc length of a given sector of a circle?

I need to calculate the area and arc length of a major sector of a 60mm diameter circle. the sector is 252 degrees. how do i do this?

Thanks in advance.

Arc length =

where r is the radius and theta is the angle in radians.

Otherwise,



for theta in degrees.

Similarly,



for theta in radians and



for theta in degrees.

That is brilliant thank you very much. another question, what formula do i use? how do i decide between radians and degrees?

Well, were you taught the formulae I gave you where theta is in radians?

Using those formulae is faster, but since you were given the angle in degrees, you better use that.

Also, you see how I got those formulae where theta is in degrees?

For the arc length, it is the circumference of a circle, multiplied by the angle divided by 360 degrees.
For the area, it is the area of a circle, multiplied by the angle divided by 360 degrees.

thats brilliant, thank you for your help.