MHB Looking Answer About Area of Circle.

  • Thread starter Thread starter susanto3311
  • Start date Start date
  • Tags Tags
    Area Circle
AI Thread Summary
The discussion focuses on finding a formula to solve a multiple-choice question regarding the area of a circle. The area of a sector is calculated using the formula A_s = (θ/360)πr², where θ represents the angle of the sector. Participants clarify that the answer of 462 pertains to the area of the sector, not the remaining area of the circle after the sector is removed. There is some confusion about whether the question asks for the area of the cut-out sector or the remaining portion. The conversation emphasizes the need for clarity in the question to avoid misinterpretation.
susanto3311
Messages
73
Reaction score
0
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
 

Attachments

  • area_problem again.png
    area_problem again.png
    4.6 KB · Views: 84
Mathematics news on Phys.org
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

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)
 
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)

the answer is 462...do you agree?
 
susanto3311 said:
the answer is 462...do you agree?

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
 
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

hi super...

thanks. i'am missing you are right...
 
Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...
Is it possible to arrange six pencils such that each one touches the other five? If so, how? This is an adaption of a Martin Gardner puzzle only I changed it from cigarettes to pencils and left out the clues because PF folks don’t need clues. From the book “My Best Mathematical and Logic Puzzles”. Dover, 1994.
Thread 'Imaginary Pythagoras'
I posted this in the Lame Math thread, but it's got me thinking. Is there any validity to this? Or is it really just a mathematical trick? Naively, I see that i2 + plus 12 does equal zero2. But does this have a meaning? I know one can treat the imaginary number line as just another axis like the reals, but does that mean this does represent a triangle in the complex plane with a hypotenuse of length zero? Ibix offered a rendering of the diagram using what I assume is matrix* notation...

Similar threads

Replies
11
Views
3K
Replies
8
Views
2K
Replies
4
Views
1K
Replies
2
Views
4K
Replies
3
Views
3K
Replies
2
Views
1K
Replies
5
Views
2K
Back
Top