How to find the ratio of diameter and circumference - ACT Math
Card 0 of 27
Let
represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
Let represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
The formula for the area of a circle is
, and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:




The formula for the area of a circle is , and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:
Compare your answer with the correct one above
A circle has a radius of
. What is the ratio of its circumference to its area?
A circle has a radius of . What is the ratio of its circumference to its area?
1. Find the circumference:


2. Find the area:


3. Divide the circumference by the area:

1. Find the circumference:
2. Find the area:
3. Divide the circumference by the area:
Compare your answer with the correct one above
How far must a racehorse run in a
lap race where the course is a circle with an area of
?
How far must a racehorse run in a lap race where the course is a circle with an area of
?
To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is
. We can then find the radius.




Because
, our diameter is 12.
We can now find the circumference.


Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.

To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is . We can then find the radius.
Because , our diameter is 12.
We can now find the circumference.
Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.
Compare your answer with the correct one above
Let
represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
Let represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
The formula for the area of a circle is
, and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:




The formula for the area of a circle is , and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:
Compare your answer with the correct one above
A circle has a radius of
. What is the ratio of its circumference to its area?
A circle has a radius of . What is the ratio of its circumference to its area?
1. Find the circumference:


2. Find the area:


3. Divide the circumference by the area:

1. Find the circumference:
2. Find the area:
3. Divide the circumference by the area:
Compare your answer with the correct one above
How far must a racehorse run in a
lap race where the course is a circle with an area of
?
How far must a racehorse run in a lap race where the course is a circle with an area of
?
To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is
. We can then find the radius.




Because
, our diameter is 12.
We can now find the circumference.


Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.

To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is . We can then find the radius.
Because , our diameter is 12.
We can now find the circumference.
Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.
Compare your answer with the correct one above
Let
represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
Let represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
The formula for the area of a circle is
, and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:




The formula for the area of a circle is , and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:
Compare your answer with the correct one above
A circle has a radius of
. What is the ratio of its circumference to its area?
A circle has a radius of . What is the ratio of its circumference to its area?
1. Find the circumference:


2. Find the area:


3. Divide the circumference by the area:

1. Find the circumference:
2. Find the area:
3. Divide the circumference by the area:
Compare your answer with the correct one above
How far must a racehorse run in a
lap race where the course is a circle with an area of
?
How far must a racehorse run in a lap race where the course is a circle with an area of
?
To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is
. We can then find the radius.




Because
, our diameter is 12.
We can now find the circumference.


Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.

To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is . We can then find the radius.
Because , our diameter is 12.
We can now find the circumference.
Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.
Compare your answer with the correct one above
Let
represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
Let represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
The formula for the area of a circle is
, and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:




The formula for the area of a circle is , and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:
Compare your answer with the correct one above
A circle has a radius of
. What is the ratio of its circumference to its area?
A circle has a radius of . What is the ratio of its circumference to its area?
1. Find the circumference:


2. Find the area:


3. Divide the circumference by the area:

1. Find the circumference:
2. Find the area:
3. Divide the circumference by the area:
Compare your answer with the correct one above
How far must a racehorse run in a
lap race where the course is a circle with an area of
?
How far must a racehorse run in a lap race where the course is a circle with an area of
?
To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is
. We can then find the radius.




Because
, our diameter is 12.
We can now find the circumference.


Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.

To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is . We can then find the radius.
Because , our diameter is 12.
We can now find the circumference.
Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.
Compare your answer with the correct one above
Let
represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
Let represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
The formula for the area of a circle is
, and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:




The formula for the area of a circle is , and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:
Compare your answer with the correct one above
A circle has a radius of
. What is the ratio of its circumference to its area?
A circle has a radius of . What is the ratio of its circumference to its area?
1. Find the circumference:


2. Find the area:


3. Divide the circumference by the area:

1. Find the circumference:
2. Find the area:
3. Divide the circumference by the area:
Compare your answer with the correct one above
How far must a racehorse run in a
lap race where the course is a circle with an area of
?
How far must a racehorse run in a lap race where the course is a circle with an area of
?
To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is
. We can then find the radius.




Because
, our diameter is 12.
We can now find the circumference.


Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.

To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is . We can then find the radius.
Because , our diameter is 12.
We can now find the circumference.
Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.
Compare your answer with the correct one above
Let
represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
Let represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
The formula for the area of a circle is
, and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:




The formula for the area of a circle is , and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:
Compare your answer with the correct one above
A circle has a radius of
. What is the ratio of its circumference to its area?
A circle has a radius of . What is the ratio of its circumference to its area?
1. Find the circumference:


2. Find the area:


3. Divide the circumference by the area:

1. Find the circumference:
2. Find the area:
3. Divide the circumference by the area:
Compare your answer with the correct one above
How far must a racehorse run in a
lap race where the course is a circle with an area of
?
How far must a racehorse run in a lap race where the course is a circle with an area of
?
To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is
. We can then find the radius.




Because
, our diameter is 12.
We can now find the circumference.


Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.

To find the answer, we need to first find the circumference of the circle then mulitply that by 4 because the racehorse is running 4 laps.
We know that the area of the circle is . We can then find the radius.
Because , our diameter is 12.
We can now find the circumference.
Multiply the circumference by 4 (our racehorse is running 4 laps) to find the answer.
Compare your answer with the correct one above
Let
represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
Let represent the area of a circle and
represent its circumference. Which of the following equations expresses
in terms of
?
The formula for the area of a circle is
, and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:




The formula for the area of a circle is , and the formula for circumference is
. If we solve for C in terms of r, we get
.
We can then substitute this value of r into the formula for the area:
Compare your answer with the correct one above
A circle has a radius of
. What is the ratio of its circumference to its area?
A circle has a radius of . What is the ratio of its circumference to its area?
1. Find the circumference:


2. Find the area:


3. Divide the circumference by the area:

1. Find the circumference:
2. Find the area:
3. Divide the circumference by the area:
Compare your answer with the correct one above