Q&A for How to Calculate the Diameter of a Circle

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What is diference between radius and diameter?

Donagan

Top Answerer

The radius is half the diameter.

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Question

If I have the circumference, how can I calculate diameter?

Donagan

Top Answerer

Divide the circumference by pi.

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Question

The radius of a dinner plate is 6 cm; what is the diameter?

Christopher

Top Answerer

Since the radius is half the diameter, to get the diameter, you'd multiply the 6 cm by 2. The diameter of this circular dinner plate is 12 cm.

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Question

What is the area of a circle?

Community Answer

The area of a circle is area=πr2, or pi * the radius squared, make sure to first square the radius then multiply that by pi.

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How do I trace a circle with a diameter of 4 cm?

Community Answer

You have a couple options. Find something that is 4 cm in diameter (or slightly smaller) and draw around it. Use a compass set to a radius of 2 cm. Use a drawing program and set the circle properties so that it has a diameter of 4 cm. Finally, use metric graph paper and plot the graph of x2 + y2 = 4. (1 unit = 1 cm).

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Question

How do I find the area of a circle that has a perimeter of 36 cm?

Donagan

Top Answerer

Divide the circumference (perimeter) by pi. That gives you the diameter. Half of that is the radius. To get the area, square the radius, and then multiply by pi.

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Question

How do I calculate the circumference of a circle to the diameter?

Danoyachtcapt

Top Answerer

C = 3.14 x d

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Question

What is the diameter of a ball with a volume of 288?

Donagan

Top Answerer

The diameter is equal to the cube root of the following: 6 times the volume divided by pi.

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Question

How can I find the coordinates of a diameter?

Community Answer

The diameter is formed from the center of one side of a circle to the other, meaning that there are no coordinates since the diameter is always located in the center of the circle.

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Question

If my radius is 20ft, how can I find the diameter?

Donagan

Top Answerer

Double the radius.

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Question

How many times greater is a circle with 24' radius than a circle with 4' radius?

Donagan

Top Answerer

24 is 6 times greater than 4. The square of 6 is 36. The larger circle is 36 times greater (in area) than the smaller circle.

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Question

I have a tree with a circumference of 38 inches. I need to know the diameter. If I try to use 3.14, it is in cm and therefore not compatible? What is the number of inches?

Technist

Community Answer

3.14 is universal, so it should work for all measurements. If the circumference is 38 inches, then all you need to do is divide it by π, or 3.14. It is approximately equal to 12.10.

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Question

So if I have the radius of 18 cm, which goes all the way across the circle, how do I find the area?

Donagan

Top Answerer

Area equals pi multiplied by the square of the radius (the radius goes only halfway across the circle).

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Question

How do I divide 20 percent by 10 percent?

Donagan

Top Answerer

Divide .20 by .10, which is the same as dividing 20 by 10.

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Question

How do I find the perimeter when they give me the circumference?

Community Answer

The circumference of a circle and the perimeter of a circle are the same, circumference is simply a word used to describe the perimeter of a curved figure or arc, such as a circles, ovals, arcs, etc.

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Question

If a car tire has a radius of 18 cm, how far will it go in 120 turns?

Forestbee

Community Answer

If the radius is 18, the circumference is 2*Pi*r = 2 *3.14 *18 = 113.04. In 120 turns, the distance travelled is 120 * circumference = 120* 113.04 = 13564.8 cm = 135.648 meters.

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Question

If I know the perimeter of a circle, how do I find the circumference?

Community Answer

In the case of a curved figure (such as a circle), the terms "perimeter" and "circumference" mean the same thing. The term "perimeter" is usually applied only to straight-sided figures.

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Question

How do I find the area of a circle, if I know the radius?

Community Answer

The area of a circle is equals to π r^2 (Pi multiplied by the radius squared).

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Question

How do I determine radius in inches, not metric?

Donagan

Top Answerer

Use the same equations as outlined above. If the diameter, circumference, or area are reported in inches or square inches, the calculated radius will be in inches. If you need to convert a radius in metric units to a radius in inches, use the conversion factor(s) shown in Convert Centimeters to Inches or a similar article.

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Question

If the circumference is 5 inches, what is the diameter?

Donagan

Top Answerer

Divide the circumference by pi.

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Question

How many diameters and radii are in a circle?

Community Answer

A circle has one diameter and one radius. Each is a measurement, and not an object contained within the shape.

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Question

What is the formula of the diameter and radius?

Community Answer

The diameter is twice the radius. In other words, d = 2r.

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Question

What is the width if I have the diameter?

Community Answer

The width of the circle IS the diameter. The width is the line going directly through the middle of the circle - the diameter.

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Question

A circular park has a circumference of 36 pi yards. What is its diameter?

Donagan

Top Answerer

The diameter is 36π / π = 36 yards.

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Question

How do I find the radius of a circle with an area of 2,826 square feet?

Donagan

Top Answerer

Divide the area by pi, then find the square root of that number.

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Question

R=5, what is the circle's diameter?

Momen Abdelsalam

Community Answer

To find the diameter, you have to multiply the radius of the object by 2. Which makes the diameter a total of 10.

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Question

I have a diameter of 4 m and I want the area; how do I do it?

Donagan

Top Answerer

Divide the diameter in half to get the radius. Square the radius. Then multiply by pi.

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Question

How do I draw a 40 cm diameter circle template without a compass?

Community Answer

Try drawing a 40 cm line. Mark the ends and the center. The center of the line will be the center of your circle. Place 20 cm or the middle of your 40 cm ruler on the center point in a different direction, such as perpendicular to the original line. Mark the ends of the 40 cm line. Do this with several intersecting, but different lines. It may look like a giant starburst or asterisk. Connect the dots of the circle. Alternative: Measure a plate or other circular item with a diameter of 40 cm. Trace it!

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Question

If minute hand of a clock is 14.4 cm long, how far will the hand travel from 12:00 to 12:15?

Community Answer

Assuming the distance between the center of the clock face and the point of the minute hand represents the radius of the circle, the point of the hand moves in an arc that measures 22.62 cm. That's one-quarter of the full circumference (because the arc between 12:00 and 12:15 is one-quarter of the full circle). The diameter (28.8 cm) multiplied by pi is 90.478 cm (the full circumference), and one-quarter of that is 22.62 cm.

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Question

How can I find the area of a circle with diameter 63mi.?

Community Answer

Divide the diameter by 2 to get the radius: 31.5 mi. Square that: 992.25 sq mi. Multiply by pi (3.14): 3,115.665 sq mi. That's the area.

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