susanto3311 said:hello all...
i'am looking for a formula to solve this multiple choice question about area of circle...
like my picture below ...
any body can help me, thanks in advance...
susanto3311
SuperSonic4 said:The area of the bit of the circle left will be area of the whole circle less the area of the cut out sector. The formulae for the area of a sector (in degrees) is given by
$$A_s = \dfrac{\theta}{360} \pi r^2$$
In this case $$\theta$$ is the angle of the sector (i.e. the missing piece in your example)
susanto3311 said:the answer is 462...do you agree?
SuperSonic4 said:I get B as my answer (although the question could stand to be clearer about whether or not it wants the area of the cut out sector or the area of "pacman" - the bit that's left).
How did you arrive at 462 (which is the area of the sector)? Don't forget that's just the area of the sector - you need to subtract this from the area of the whole