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# Sectors

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1. Sectors
A Circle has a radius of 5.5cm
the length of the arch of the sector is 6.72cm
Work out the size of the angle x of the sector.
2. Re: Sectors
I've worked it out now
3. Re: Sectors
what did you get for the answer?
4. Re: Sectors
(Original post by Dreamer 160)
what did you get for the answer?
70
5. Re: Sectors
How do I do this question

The diagram shows a sector of a circle.
The area of the sector is 17.453cm^2
Work out the radius of the circle.
Sector =80
Last edited by zed963; 06-08-2012 at 15:32.
6. Re: Sectors
(Original post by zed963)
How do I do this question

The diagram shows a sector of a circle.
The area of the sector is 17.453cm^2
Work out the radius of the circle.
Sector =80
I assume you mean that the sector angle is 80 degrees.

Well how do you work out the area of a sector:

,

where is the sector angle and r is the radius of the circle. So in this question you have

Can you solve this equation to find r?
Last edited by notnek; 06-08-2012 at 15:51.
7. Re: Sectors
(Original post by notnek)
I assume you mean that the sector angle is 80 degrees.

Well how do you work out the area of a sector:

,

where is the sector angle and r is the radius of the circle. So in this question you have

Can you solve this equation to find r?
I'm struggling on rearranging it.

First I would 80/360 = 0.22222 and then 17.4/0.222*pi
8. Re: Sectors
(Original post by zed963)
I'm struggling on rearranging it.

First I would 80/360 = 0.22222 and then 17.4/0.222*pi
Yes and so you're left with r^2. So square root your answer to find r.

When you work it out on your calculator, don't round the numbers like you did in your last post. You should type in

9. Re: Sectors
(Original post by notnek)
Yes and so you're left with r^2. So square root your answer to find r.

When you work it out on your calculator, don't round the numbers like you did in your last post. You should type in

Thats what I did and I got the answer to be 2.357 but the book states that the answer is 5
10. Re: Sectors
(Original post by zed963)
Thats what I did and I got the answer to be 2.357 but the book states that the answer is 5
I just typed it in and got approximately 5.

You must be making a calculator error.
11. U need help on angles I do not understand them plz help

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12. Re: Sectors
(Original post by notnek)
I just typed it in and got approximately 5.

You must be making a calculator error.

True.
13. Re: Sectors
(Original post by aliyah.k)
U need help on angles I do not understand them plz help

This was posted from The Student Room's iPhone/iPad App
You may want to rephrase what you have just said.
14. (Original post by zed963)
You may want to rephrase what you have just said.
Oops yep sorry I need help on angles I don't understand them. Also how to do hard times tables a easy way plz help.

This was posted from The Student Room's iPhone/iPad App
15. Re: Sectors
(Original post by aliyah.k)
Oops yep sorry I need help on angles I don't understand them. Also how to do hard times tables a easy way plz help.

This was posted from The Student Room's iPhone/iPad App
What aspects of the angles topic do you not understand?

What do you consider hard times tables?
16. Re: Sectors
Guys, listen to Mr M. He's a mathematical legend of TSR. And he can give you detentions.
17. Re: Sectors
(Original post by Lunch_Box)
And he can give you detentions.
A hard stare is usually enough.
18. Re: Sectors
(Original post by Mr M)
A hard stare is usually enough.
19. Re: Sectors
(Original post by aliyah.k)
Oops yep sorry I need help on angles I don't understand them. Also how to do hard times tables a easy way plz help.

This was posted from The Student Room's iPhone/iPad App
There are tricks out there for multiplying etc. but you should at least know your time table up to 10.

As for the angles just watch some videos and read a book about it, if there's a question that your're stuck on then please don't hesitate to post it on the forum.

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Last updated: August 6, 2012
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