Question

Will Medal !! Can someone teach me how to find the area of a sector?

Answer 1

Okay?

Answer 2

Read this, http://www.regentsprep.org/regents/math/geometry/gp16/circlesectors.htm

Answer 3

Got it?

Answer 4

not really

Answer 5

oh.

Answer 6

I found this, :
Notice that when finding the area of a sector, you are actually finding a fractional part of the area of the entire circle. The fraction is determined by the ratio of the central angle of the sector to the "entire central angle" of 360 degrees, or by the ratio of the arc length to the entire circumference.

Answer 7

@ganeshie8

Answer 8

I'm sorry, I have to go, please, study the website that I gave you and read it a few times! :D

Answer 9

Please give me a specific example to discuss. That might make it easier for you to connect with this procedure of finding the area of a sector of a circle.

Answer 10

Ok give me like 2 min.

Answer 11

@mathmale

Answer 12

The circle shown below has a diameter of 12 centimeters. What is the approximate area of the shaded sector?


A. 390 cm2
B. 226 cm2
C. 97 cm2
D. 102 cm2

Answer 13

http://media.apexlearning.com/Images/201003/10/77cec6b2-deb0-43e9-83a2-33c7596f7f69.gif

Answer 14

First, you need to find the radius. The radius is simply half the diameter. So, the radius is ... ?

Answer 15

Sorry my school was having an earthquake drill

Answer 16

You also need to mention the "central angle."

Was one given in the problem you've shared?

Answer 17

Earthquate drill? Scary?

Answer 18

yeah thats common where i live

Answer 19

not at all scary

Answer 20

How about the "central angle" of your sample sector?

This sector has a radius of ... ? and a central angle of ... ?

Answer 21

would it be half of 310

Answer 22

??

Answer 23

155

Answer 24

Are those "central angles" actually marked on a picture of a sector?

If not, just invent a central angle between zero and 360 degrees, or between 0 and 2pi radians.

Answer 25

oh so it would be some number 2x3.14x some number.

Answer 26

No, I'm asking that you arbitrarily choose some central angle. Let me draw a sample sector:

Answer 27

ok

Answer 28

choose a central angle in either degrees or radians.
Again, give me an (arbitrary) radius of the sector.

Answer 29

ok so 10

Answer 30

Is that the central angle or is that the radius? I need both.

central angle:

radius:

Answer 31

central angle 20 is the radiud

Answer 32

All right.
1. First we find the area of the circle. That is A=pi r^2.
2. Next, we set up a proportion:

10 degrees (your central angle) 1
-------------------------- = ----
360 degrees is a full circle 36

Answer 33

then the area of the sector defined by a radius of 20 and a central angle of 10
is

(1/36)*pi(20)^2. simplify that, and then you'll be done. Please do this. Leave "pi" as it is; don't use 3.14 ga

Answer 34

ok let me put it in my calculator

Answer 35

34.90

Answer 36

??

Answer 37

(1/36)(400)pi

(1/36) of 400 is about 10 or 10.5. Multiplied by pi, that's around 35. So, yes, your estimate of the area of the sector is quite good.

Answer 38

Notice that when finding the area of a sector, you are actually finding a fractional part of the area of the entire circle. The fraction is determined by the ratio of the central angle of the sector to the "entire central angle" of 360 degrees, or by the ratio of the arc length to the entire circumference.

Answer 39

@mathmale can u come back to my question

Answer 40

so do i multiply to by 310 next

Answer 41

No, you're done.

Area of sector (central angle measured in degrees) is

Central angle
--------------- (circle radius )^2 * pi.
360

Answer 42

so thats the ansewr to my question

Answer 43

@ mathmale what the ansewer

Answer 44

@mathmale

Answer 45

I still dont understand this

Answer 46

please help

Answer 47

Are you finding the area of the blue region or the white region? Both are sectors of a circle.

Answer 48

just the sector

Answer 49

Both are sectors.

Answer 50

let me get you a new example

Answer 51

no

Answer 52

Not in this thread. This thread is already too long.

I'll help you with the problem you previously posted in this thread.

Answer 53

i already finishded that and missed it so

Answer 54

I am asking if you are finding the area of the blue-shaded sector or the white-shaded sector.

Answer 55

Well, open a new thread and post the new problem. Start fresh.

Answer 56

ok