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# Circles C2 watch

1. The area of a segment is 20cm^2 and the angle subtended by the chord forming the segment is 1.3 radians. What is the radius of the circle?
2. a = 0.5r^2 (theta)

r= 5.54 cm
3. The first question was just putting numbers into the formula for area of a segment.

Another little area of segments question.

A chord divides a circle into 2 areas, in the ratio 3:1.

What is the angle between the chord and a diameter drawn from one of its endpoints?
4. (Original post by callum Honisett)
a = 0.5r^2 (theta)

r= 5.54 cm
http://www.mathsisfun.com/geometry/i...cle-slices.gif

The area of the segment is 20cm2 - not the area of the sector.
5. (Original post by stevencarrwork)
The first question was just putting numbers into the formula for area of a segment.

Another little area of segments question.

A chord divides a circle into 2 areas, in the ratio 3:1.

What is the angle between the chord and a diameter drawn from one of its endpoints?
6. (Original post by Narik)
http://www.mathsisfun.com/geometry/i...cle-slices.gif

The area of the segment is 20cm2 - not the area of the sector.
Oh sorry must have msiread it

I'll get to it in a minute.
7. (Original post by Narik)
http://www.mathsisfun.com/geometry/i...cle-slices.gif

The area of the segment is 20cm2 - not the area of the sector.
(0.5r^2 theta) - (0.5r^2sintheta) = 20

(you know theta, can't remember what you said it was)
8. CALLUM

ME

I see where you are coming from, but that would be the angle joining the other end of the chord to the diameter drawn from the first end.

That line is a distraction. (Or at least I think there is an easier way)
9. (Original post by Narik)
http://www.mathsisfun.com/geometry/i...cle-slices.gif

The area of the segment is 20cm2 - not the area of the sector.
In that case you will need the 0.5*a*b*SinC rule as well.
10. Just use this formula:

And rearrange to find r.

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