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Q: Do you need a diameter or a radius for the area of a circle?

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When the diameter is 2.9 the radius is 1.45. To find the area of a circle you need to use this formula r2*pi In this case it will be 1.45*1.45*3.14=6.6

Since the area of a circle can be represented by the equation A=πr², to find the are of a circle you merely need to fill in the variables. The radius is half of the diameter, so a circle with a diameter of 4.4 cm has a radius of 2.2 cm. A=π(2.2)². First, square 2.2 and you will get 4.84. Then, multiply 4.84 by pi and you will get approximately 15.2. The area of a circle with a diameter of 4.4 cm is approximately 15.2 square cm.

To find the circumference of a circle, you need only know the radius or diameter of the circle. The circumference of a circle is calculated as 2 x Pi x radius OR Pi x diameter. Pi is approximately 3.1415926.

The short answer is that all circles are geometrically similar. Ignoring the circle's position, you need a single number to characterize the circle. The idea is that the diameter of the circle is always 2 times the radius, the circumference is equal to the radius times 2 times pi, and the area is calculated as pi times radius squared.

If you're only given the length of the arc, then you can't. You also need to know the fraction of the circle that's in the sector. You can figure that out if you know the angle of the arc, or the radius or diameter of the circle. -- Diameter of the circle = 2 x (radius of the circle) -- Circumference of the circle = (pi) x (Diameter of the circle) -- (length of the arc)/(circumference of the circle) = the fraction of the whole circle that's in the sector or -- (degrees in the arc)/360 = the fraction of the whole circle that's in the sector -- Area of the circle = (pi) x (radius of the circle)2 -- Area of the sector = (Area of the circle) x (fraction of the whole circle that's in the sector)

Related questions

If you have the circumference: circumference = (pi) * diameter diameter = circumference / (pi) If you have the area: area = (pi) * radius * radius radius = square_root(area / pi) radius = diameter / 2 diameter = 2 * square_root(area / pi)

To calculate this you will need the diameter of the circle. The formula is: diameter/2*pi If you don't know the diameter you can also use the area of the circle: Sqrt(Area/pi) = radius

Use the formula for the area of a circle (A = pi x radius2). Replace the data you know (the area), and solve for radius. Then, you can double this radius to get the diameter.

Area = Pi(radius)squared. You only need the radius of a circle to find the area. To find the radius, when you have the diameter, divide the diameter by 2, because the diameter forms two radii. After you have found the radius, plug in the radius into the area equation: Area = Pi(radius)squared In other words, you can say the other equation for the area of a circle is: Area = Pi(1/2Diameter)squared

The circle must have a diameter, so maybe your teacher just didn't tell you the diameter. In order to figure out the question, you need to know some information about the circle. Weather it's the radius, circumference, or diameter. So here's how you find area if you only have each of the three: 1. If you just have the radius, then square the radius. This means multiply radius times radius. Or say the radius is 4. Squaring it is 4 times 4. So once you find out the answer for radius squared, multiply radius squared by pi. (Probably use 3.14 for pi) Then there's your area. 2. If you only have the circumference of a circle, then you need to find the radius. In order to do that, you need to find the diameter. To find the diameter of a circle, you take the circumference and divide it by pi. (3.14) then you have your diameter. Since the radius is half the diameter, divide the diameter by 2. Then, once you find the radius, you may look at step 1 and use those steps to find out the area. Since your question is wondering how to find the area without knowing the diameter, then you can multiply the radius by 2 to find out the diameter. Even though you don't need to know the diameter to find the area. You just do (r times r) times pi (3.14)

12 x 12 sounds like a square, not like a circle. To specify a circle, you need a single number, for example the radius or the diameter. Assuming the diameter is 12, the radius would be half of that (6 units). The "size" of the circle can be considered this radius (6), the diameter (12), or the area calculated by the formula pi * radius * radius.

When the diameter is 2.9 the radius is 1.45. To find the area of a circle you need to use this formula r2*pi In this case it will be 1.45*1.45*3.14=6.6

Assuming you are referring to a circle: the formula for the area is A = pi x radius squared. To solve for the radius, divide the area by pi, and take the square root.Since you want the diameter, you will then need to multiply the radius by 2.

Since the area of a circle can be represented by the equation A=πr², to find the are of a circle you merely need to fill in the variables. The radius is half of the diameter, so a circle with a diameter of 4.4 cm has a radius of 2.2 cm. A=π(2.2)². First, square 2.2 and you will get 4.84. Then, multiply 4.84 by pi and you will get approximately 15.2. The area of a circle with a diameter of 4.4 cm is approximately 15.2 square cm.

To find the circumference of a circle, you need only know the radius or diameter of the circle. The circumference of a circle is calculated as 2 x Pi x radius OR Pi x diameter. Pi is approximately 3.1415926.

If you have the radius, then area = pi*r2 which you then round to the nearest hundredth. If you do not know the radius but do know the diameter or circumference, you can calculate the radius. Otherwise you need to measure it.

The short answer is that all circles are geometrically similar. Ignoring the circle's position, you need a single number to characterize the circle. The idea is that the diameter of the circle is always 2 times the radius, the circumference is equal to the radius times 2 times pi, and the area is calculated as pi times radius squared.

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