oh sorry, I used radians.(Original post by Tinkletea)
I thought the formula to find the area of a sector was theta / 360 x pi x r^2?

L'Evil Fish
 Follow
 302 followers
 18 badges
 Send a private message to L'Evil Fish
Offline18ReputationRep: Follow
 21
 27032013 12:37

Indeterminate
 Follow
 162 followers
 3 badges
 Send a private message to Indeterminate
 Political Ambassador
Offline3ReputationRep:Political Ambassador Follow
 22
 27032013 12:40
(Original post by Tinkletea)
I thought the formula to find the area of a sector was theta / 360 x pi x r^2? 
 Follow
 23
 27032013 12:49
I seem to use a different method which I find easier, I will input and I do apologise if I am incorrect, I am self teaching Maths and so I do get muddled at times. But this what I got.
To work out feta =
Arc length = feta /360 x 2 x pi x r. We know Arc length = 15. Therefore
15 = feta / 360 x 2 x pi x r.
To work this out, multiply arc length by 360 and divide by 2 x pi x r =
15 x 360 / 2 x pi x 10 = 85.9436692696 = feta.
Therefore you can now work the area out.
Area of sector = feta / 360 x pi x r^2 therefore =
85.9436692696 / 360 x pi x 10^2 = 75^2.
I find this method very easy. 
L'Evil Fish
 Follow
 302 followers
 18 badges
 Send a private message to L'Evil Fish
Offline18ReputationRep: Follow
 24
 27032013 12:51
(Original post by Tinkletea)
I seem to use a different method which I find easier, I will input and I do apologise if I am incorrect, I am self teaching Maths and so I do get muddled at times. But this what I got.
To work out feta =
Arc length = feta /360 x 2 x pi x r. We know Arc length = 15. Therefore
15 = feta / 360 x 2 x pi x r.
To work this out, multiply arc length by 360 and divide by 2 x pi x r =
15 x 360 / 2 x pi x 10 = 85.9436692696 = feta.
Therefore you can now work the area out.
Area of sector = feta / 360 x pi x r^2 therefore =
85.9436692696 / 360 x pi x 10^2 = 75^2.
I find this method very easy.
It is THETA 
 Follow
 25
 27032013 13:00
(Original post by Tinkletea)
I seem to use a different method which I find easier, I will input and I do apologise if I am incorrect, I am self teaching Maths and so I do get muddled at times. But this what I got.
To work out feta =
Arc length = feta /360 x 2 x pi x r. We know Arc length = 15. Therefore
15 = feta / 360 x 2 x pi x r.
To work this out, multiply arc length by 360 and divide by 2 x pi x r =
15 x 360 / 2 x pi x 10 = 85.9436692696 = feta.
Therefore you can now work the area out.
Area of sector = feta / 360 x pi x r^2 therefore =
85.9436692696 / 360 x pi x 10^2 = 75^2.
I find this method very easy. 
 Follow
 26
 27032013 13:02
Yeah I agree. Joys of 'Ans' on my calculator though.

yellowcopter
 Follow
 55 followers
 21 badges
 Send a private message to yellowcopter
 Thread Starter
Offline21ReputationRep: Follow
 27
 27032013 16:56
(Original post by Tinkletea)
I seem to use a different method which I find easier, I will input and I do apologise if I am incorrect, I am self teaching Maths and so I do get muddled at times. But this what I got.
To work out feta =
Arc length = feta /360 x 2 x pi x r. We know Arc length = 15. Therefore
15 = feta / 360 x 2 x pi x r.
To work this out, multiply arc length by 360 and divide by 2 x pi x r =
15 x 360 / 2 x pi x 10 = 85.9436692696 = feta.
Therefore you can now work the area out.
Area of sector = feta / 360 x pi x r^2 therefore =
85.9436692696 / 360 x pi x 10^2 = 75^2.
I find this method very easy.
Just need to remember the equation you used now.
Posted from TSR Mobile 
L'Evil Fish
 Follow
 302 followers
 18 badges
 Send a private message to L'Evil Fish
Offline18ReputationRep: Follow
 28
 27032013 17:02
(Original post by yellowcopter)
Thanks for that, it explained to me that you find out Theta, I though it was a symbol for a number like pi.
Just need to remember the equation you used now.
Posted from TSR Mobile
x/360 = the fraction of the circle it is.
Pi * r^2 = area of a full circle 
yellowcopter
 Follow
 55 followers
 21 badges
 Send a private message to yellowcopter
 Thread Starter
Offline21ReputationRep: Follow
 29
 27032013 17:09
(Original post by L'Evil Fish)
It's basically asking what fraction of the circle it has for theta.
x/360 = the fraction of the circle it is.
Pi * r^2 = area of a full circle
What's x in x/360? So confused! My teacher never teaches us above D/C grade, very annoying and confuses me when I try to do higher grade questions!
Posted from TSR Mobile 
 Follow
 30
 27032013 17:11
(Original post by yellowcopter)
What fraction of the circle does that angle start at? 'Fraction of the circle it has theta' doesn't make sense to me.
What's x in x/360? So confused! My teacher never teaches us above D/C grade, very annoying and confuses me when I try to do higher grade questions!
Posted from TSR Mobile 
L'Evil Fish
 Follow
 302 followers
 18 badges
 Send a private message to L'Evil Fish
Offline18ReputationRep: Follow
 31
 27032013 17:12
(Original post by yellowcopter)
What fraction of the circle does that angle start at? 'Fraction of the circle it has theta' doesn't make sense to me.
What's x in x/360? So confused! My teacher never teaches us above D/C grade, very annoying and confuses me when I try to do higher grade questions!
Posted from TSR Mobile
x is the angle should have made ir clearer, sorry 
yellowcopter
 Follow
 55 followers
 21 badges
 Send a private message to yellowcopter
 Thread Starter
Offline21ReputationRep: Follow
 32
 27032013 18:10
Posted from TSR Mobile 
L'Evil Fish
 Follow
 302 followers
 18 badges
 Send a private message to L'Evil Fish
Offline18ReputationRep: Follow
 33
 27032013 18:15
(Original post by yellowcopter)
MAKES SOOOOOO MUCH MORE SENSE than using theta, THANK YOU!
Posted from TSR Mobile 
 Follow
 34
 27032013 19:51
(Original post by yellowcopter)
Thanks for that, it explained to me that you find out Theta, I though it was a symbol for a number like pi.
Just need to remember the equation you used now.
Posted from TSR Mobile
The way I remember it is by remembering by knowing the basics behind it:
Arc length is the distance around the sector, what is circumference? the distance around the circle. Therefore to find out the circumference (arc length) of the sector, you just do theta / 360 (the angle of the sector, if given, divided by a full circle (360) x 2 x pi x r. What is 2 x pi x r? why its the formula of working out a circumference. I found it took me a little while to get that, but once I did its stuck. Just remember arc length is just the same as the circumference( although do remember the sides if asked for the perimeter of the sector), therefore its much easier to remember the formula associated with the arc length
Same goes for the area, use the angle (if given) divided by the full circle, x pi x r^2... pi x r^2? the area of a circle.
I'm not being patronising by the way, I have found it very difficult, it took me a while to get this. I left school early and therefore didn't get taught much, especially to this standard so I know its so important to really get whats obvious to others, first before you can work on the harder stuff.
Once you understand the concepts behind it, it will be easier to try harder questions.
If you are given the angle and radius, but not the arc length, look at the formula for finding arc length.
Arc length = theta / 360 x (2 x pi x r). Since you know the angle, you can plug that in, work it out and you will find the arc length.
To find the angle, if you are given arc length.
As above, if you know the arc length you can find the angle just by rearranging what you know.
theta / 360 x 2 x pi x r = arc length. So to get feta on its own you need multiply the arc length by 360 and divide by 2 x pi x r. then of course when you know the angle, you can plug it into the area formula to find the area.
Same goes if you know the area and radius. Look at the formula and see what you can do to find theta. = Area = theta / 360 x pi x r^2. This is very similar to above, all you would need to do is multiply the area by 360 and divide it by pi and r^2.
If you have the area and angle, you can find the radius by doing some rearranging again.
Again, please don't see this as patronising as it took me a while of sitting watching videos etc to get it because I did not know the basics and therefore I was running before I could jump. I would definitely recommend youtube, there is some very good videos on there. When I first looked at these, I thought it was going to be another 'ill leave that one out' like vectors, but watched a few videos and I get it now.
HTH
Edit: Here is the video that really 'drilled it' for me. http://www.youtube.com/watch?v=WIpdloZ0v78Last edited by Tinkletea; 27032013 at 19:56.
 1
 2
 Edexcel GCSE Maths Paper 1 Help Thread
 GCSE edexcel spec?
 Edexcel GCSE Mathematics A Higher Tier 1MA0/1H  6th ...
 GCSE (91)Edexcel Maths
 Edexcel GCSE Mathematics A Higher Tier 1MA0/1H  4th ...
 Mathematics GCSE Edexcel A  Topics
 Edexcel GCSE Mathematics A Higher Paper 2016 Unofficial ...
 Maths igcse paper 4
 Edexcel Mathematics A (Linear) from 2010 Specification
 The hard grade 9 maths questions thread 2017

University of Glasgow

Mathematics and Music with a Year Abroad
Cardiff University

University of Oxford

Durham University

University of Bedfordshire

University of Surrey

Durham University

Lancaster University

Mathematics and Computer Science (with an Industrial Year)
University of Birmingham

University of Surrey
We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.
 SherlockHolmes
 Notnek
 charco
 Mr M
 Changing Skies
 F1's Finest
 rayquaza17
 RDKGames
 davros
 Gingerbread101
 Kvothe the Arcane
 TeeEff
 The Empire Odyssey
 Protostar
 TheConfusedMedic
 nisha.sri
 claireestelle
 Doonesbury
 furryface12
 Amefish
 harryleavey
 Lemur14
 brainzistheword
 Rexar
 Sonechka
 TheAnxiousSloth
 EstelOfTheEyrie
 CoffeeAndPolitics
 an_atheist
 Labrador99
 EmilySarah00