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A circle is the locus of all points equidistant from a fixed point on the plane. The fixed point is called the centre of the circle and the equal distance is called the radius of the circle.

We can derive the equation of the circle from the distance formula.

Let O be the centre of the circle and r be the radius of the circle.

Here the centre = Origin = (0, 0) and the radius = r units.

The distance r = sqrt ((x-0)2 + (y-0)2)

r = sqrt (x2 + y2)

Squaring both the sides, we get x2 + y2 = r2

This is the equation of the circle with centre as Origin.

If the centre point is some (h, k), then use the distance formula to find the radius r.

The distance r = sqrt ((x-h)2 + (y-k)2)

Squaring both sides, we get (x-h)2 + (y-k)2 = r2.

This is the equation of the circle with centre as the point (h, k).

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Q: How do you find the equation of a circle?

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Circumference ("perimeter") of a circle = (pi) x (diameter of the circle)

Type your answer here. Find the radius for a circle with the equation x2 plus y2 equals 9? ..

Area of a circle = (pi) (R2)R = radius of the circle = 1/2 of its diameter

The inner circle is x2 + y2 = 4. The radius of the inner circle is the square root of 4, which is 2. To find the radius of the outer circle, multiply 2 times 4. The radius of the outer circle is 8. Square 8 (82 or 8 x 8) to find the number to put into the equation of the outer circle. This is 64. The equation for the outer circle is x2 + y2 = 64.

If you have the radius of the circle then just plug it into the equation which ispi x r2This equation is used to find the area of a circleSo if your radius is 5 then all you do is 52 and then multiply by piHope that helps.Jamz159

π×(radius)2http:/www.mathwarehouse.com/geometry/circle/area-of-circle.php

Area of a circle = 3.14 * r2 Thus, radius, r = root of ( Area of a circle / 3.14 ) --------- equation 1 Circumference of circle = 2 * 3.14 * r Therefore, from (equation 1), Circumference = 2 * 3.14 * root of ( Area of a circle / 3.14 ). In a nutshell, first find the radius and then the circumference.

Equation of the circle: (x-3)^2 +( y+13)^2 = 169

The unit circle is a circle that can be used to find trigonometric functions. The equation of the unit circle is x^2 + y^2 = 1. So it is any circle with radius 1.

There are probably several ways to approach it; one general equation for the circle is: (x - a)2 + (y - b)2 = r2 This describes a circle with center at coordinates (a, b), and with a radius of r.

The area of a circle is given by the equation A=πr2.To solve for r, divide both sides by π, then take the square root of both sides of the equation.This leaves you with the equation r=sqrt(A/π)

Use this equation to find the area of a circleA=pi*r^2where r is the radius of the circle and A is the areaA=pi*6^2A=pi*36≈113 feet

a diameter

Area of the circle in square inches = pi*82

circumference of a circle = diameter*pi or 2*pi*radius

If the circumstance of a circle is 108pi then what is the radius of the circle

The radius of a circle = the diameter of the circle divided by 2

The equation for a circle is a function in that it can be graphed and charted. One common equation is x^2 + y^2 = r^2.

You cannot SOLVE a circle. You can find the radius of a circle, or its diameter, or circumference or area. Or you can find the equation of a circle in the Cartesian system or in polar coordinates. Or find other characteristics of the circle. In any case, a circle cannot have an area of 24 centemeter. Apart from the fact that there is no such word - try centimetre (or centimeter). A centimetre is a measure of length, not area.

By using the equation 2πr that is used to find the circumference, you get 12.56m

multiple the diameter by 2 to get the radius, then use your equation and go from there

area of a circle = pi*r2

OK, SO to find the area of a circle, you find the radius (half of the diameter), and fit it into the equation πr2=A where r equals radius and A = area. The perimeter of a circle is π multiplied by the diameter. π is ≈ 3.1415296.

To find the circumference of a circle the equation would be pi multiplied by diameter, or radius squared. the answer would be 31.415 units squared.

Circumference of circle: 4*pi = 12.566 cm to 3 decimal places