Finding components of a circle.
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I'm working on some summer problems so that I can be more prepared when I go into my class in the fall. I found a website full of problems of the content we will be learning but it doesn't have the answers. I need a little guidance on how to do this problem.
The following diagram shows a circle with centre o and radius 5 cm.
The points A, B, and C like on the circumference of the circle, and $angle AOC$ = 0.7 radians.
a. Find the length of the arc ABC.
b. Find the perimeter of the shaded sector.
c. Find the area of the shaded sector.
For a, the arc length would be the angle multiplied by the radius, correct?
l = 5 x 0.7
l = 3.5 cm
For b, would it be 2 radii and the length of the arc added together?
5+5+3.5 = 13.5 cm
And for c, IâÂÂm honestly not too sure. Is it the central angle over 360ð = the sector over $ÃÂr^2$
circle
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up vote
3
down vote
favorite
I'm working on some summer problems so that I can be more prepared when I go into my class in the fall. I found a website full of problems of the content we will be learning but it doesn't have the answers. I need a little guidance on how to do this problem.
The following diagram shows a circle with centre o and radius 5 cm.
The points A, B, and C like on the circumference of the circle, and $angle AOC$ = 0.7 radians.
a. Find the length of the arc ABC.
b. Find the perimeter of the shaded sector.
c. Find the area of the shaded sector.
For a, the arc length would be the angle multiplied by the radius, correct?
l = 5 x 0.7
l = 3.5 cm
For b, would it be 2 radii and the length of the arc added together?
5+5+3.5 = 13.5 cm
And for c, IâÂÂm honestly not too sure. Is it the central angle over 360ð = the sector over $ÃÂr^2$
circle
We can use the fact that the area is proportional to the angle.
â gimusi
Aug 6 at 20:14
add a comment |Â
up vote
3
down vote
favorite
up vote
3
down vote
favorite
I'm working on some summer problems so that I can be more prepared when I go into my class in the fall. I found a website full of problems of the content we will be learning but it doesn't have the answers. I need a little guidance on how to do this problem.
The following diagram shows a circle with centre o and radius 5 cm.
The points A, B, and C like on the circumference of the circle, and $angle AOC$ = 0.7 radians.
a. Find the length of the arc ABC.
b. Find the perimeter of the shaded sector.
c. Find the area of the shaded sector.
For a, the arc length would be the angle multiplied by the radius, correct?
l = 5 x 0.7
l = 3.5 cm
For b, would it be 2 radii and the length of the arc added together?
5+5+3.5 = 13.5 cm
And for c, IâÂÂm honestly not too sure. Is it the central angle over 360ð = the sector over $ÃÂr^2$
circle
I'm working on some summer problems so that I can be more prepared when I go into my class in the fall. I found a website full of problems of the content we will be learning but it doesn't have the answers. I need a little guidance on how to do this problem.
The following diagram shows a circle with centre o and radius 5 cm.
The points A, B, and C like on the circumference of the circle, and $angle AOC$ = 0.7 radians.
a. Find the length of the arc ABC.
b. Find the perimeter of the shaded sector.
c. Find the area of the shaded sector.
For a, the arc length would be the angle multiplied by the radius, correct?
l = 5 x 0.7
l = 3.5 cm
For b, would it be 2 radii and the length of the arc added together?
5+5+3.5 = 13.5 cm
And for c, IâÂÂm honestly not too sure. Is it the central angle over 360ð = the sector over $ÃÂr^2$
circle
edited Aug 6 at 20:15
asked Aug 6 at 20:04
Ella
999
999
We can use the fact that the area is proportional to the angle.
â gimusi
Aug 6 at 20:14
add a comment |Â
We can use the fact that the area is proportional to the angle.
â gimusi
Aug 6 at 20:14
We can use the fact that the area is proportional to the angle.
â gimusi
Aug 6 at 20:14
We can use the fact that the area is proportional to the angle.
â gimusi
Aug 6 at 20:14
add a comment |Â
1 Answer
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1
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For point $a$ and $b$ your answers are correct.
For the area we have that for the whole circle
- $A(2pi)=pi r^2=frac12 cdot 2picdot r^2$
therefore for an angle $theta$ since the area is proportional to the angle
- $A(theta)=frac12 theta r^2$
with $theta$ expressed in radians.
1
Using this formula, I entered A = 1/2 x 0.7 x $5^2$ and got 8.75$cm^2$ as my answer. Does this sound right?
â Ella
Aug 6 at 20:19
1
@Ella Yes exactly that's correct!
â gimusi
Aug 6 at 20:21
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
accepted
For point $a$ and $b$ your answers are correct.
For the area we have that for the whole circle
- $A(2pi)=pi r^2=frac12 cdot 2picdot r^2$
therefore for an angle $theta$ since the area is proportional to the angle
- $A(theta)=frac12 theta r^2$
with $theta$ expressed in radians.
1
Using this formula, I entered A = 1/2 x 0.7 x $5^2$ and got 8.75$cm^2$ as my answer. Does this sound right?
â Ella
Aug 6 at 20:19
1
@Ella Yes exactly that's correct!
â gimusi
Aug 6 at 20:21
add a comment |Â
up vote
1
down vote
accepted
For point $a$ and $b$ your answers are correct.
For the area we have that for the whole circle
- $A(2pi)=pi r^2=frac12 cdot 2picdot r^2$
therefore for an angle $theta$ since the area is proportional to the angle
- $A(theta)=frac12 theta r^2$
with $theta$ expressed in radians.
1
Using this formula, I entered A = 1/2 x 0.7 x $5^2$ and got 8.75$cm^2$ as my answer. Does this sound right?
â Ella
Aug 6 at 20:19
1
@Ella Yes exactly that's correct!
â gimusi
Aug 6 at 20:21
add a comment |Â
up vote
1
down vote
accepted
up vote
1
down vote
accepted
For point $a$ and $b$ your answers are correct.
For the area we have that for the whole circle
- $A(2pi)=pi r^2=frac12 cdot 2picdot r^2$
therefore for an angle $theta$ since the area is proportional to the angle
- $A(theta)=frac12 theta r^2$
with $theta$ expressed in radians.
For point $a$ and $b$ your answers are correct.
For the area we have that for the whole circle
- $A(2pi)=pi r^2=frac12 cdot 2picdot r^2$
therefore for an angle $theta$ since the area is proportional to the angle
- $A(theta)=frac12 theta r^2$
with $theta$ expressed in radians.
answered Aug 6 at 20:10
gimusi
65.5k73684
65.5k73684
1
Using this formula, I entered A = 1/2 x 0.7 x $5^2$ and got 8.75$cm^2$ as my answer. Does this sound right?
â Ella
Aug 6 at 20:19
1
@Ella Yes exactly that's correct!
â gimusi
Aug 6 at 20:21
add a comment |Â
1
Using this formula, I entered A = 1/2 x 0.7 x $5^2$ and got 8.75$cm^2$ as my answer. Does this sound right?
â Ella
Aug 6 at 20:19
1
@Ella Yes exactly that's correct!
â gimusi
Aug 6 at 20:21
1
1
Using this formula, I entered A = 1/2 x 0.7 x $5^2$ and got 8.75$cm^2$ as my answer. Does this sound right?
â Ella
Aug 6 at 20:19
Using this formula, I entered A = 1/2 x 0.7 x $5^2$ and got 8.75$cm^2$ as my answer. Does this sound right?
â Ella
Aug 6 at 20:19
1
1
@Ella Yes exactly that's correct!
â gimusi
Aug 6 at 20:21
@Ella Yes exactly that's correct!
â gimusi
Aug 6 at 20:21
add a comment |Â
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We can use the fact that the area is proportional to the angle.
â gimusi
Aug 6 at 20:14