How to calculate the equation of a circle

Graphs can graph most mathematical functions, showing them visually. A linear equation, such as "y = 2x + 3", appears on the graph as a straight line. A second-degree equation, such as "y = 3x ^ 2 + 2x + 3, " appears as a parabola. Circles in the graphs also have equations, which combine multiple quadratic expressions. The variables in the equation that determine the size of the circle and the position produce the radius of the circle, its center point and the coordinates of a point on its circumference.

You will need to:

Pencil
Paper

Steps to follow:

one

Find the coordinates of the center point of the circle. For this example, imagine a center at point (3, 4), whose x coordinate is 3 and whose y coordinate is 4.

two

Assign the variable "h" to the coordinate center x. In this case, h equals 3.

3

Assign the variable "k" to the coordinate center x. In this case, k equals 4.

4

Find the point on the circumference of the circle just below the center point. This point can, for example, have the coordinates (3, -2).

5

Subtract the point y from the coordinate k - 4 - (-2) = 6. This is the radius of the circle.

6

Make the square of the radius - 6 ^ 2 = 36. Assign this value the variable "s".

7

Enter the values you have calculated in the following equation - (x - h) ^ 2 + (y - k) ^ 2 = s. In this example, (x - 3) ^ 2 + (y - 4) ^ 2 = 36. This is the equation of the circle.