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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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
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.
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
a diameter