Circle Equation: General Form
General Form of the Circle Equation
There is another way to express circle equations apart from its standard form , and that is to express it in the general form
where a, b, and c are constants.
Converting General Form to Standard Form
In this section, you will learn how to convert the general form of the circle equation to its standard form.
By converting from the general form to the standard form, you can read off quite easily where the coordinates of the centre of the circle is, and also its radius.
In the example above, we have the center with radius .
Prerequisite knowledge required: completing the square. (Watch Completing the Square Part 1 | Part 2 | Part 3)
Suppose we have an equation of a circle in the general form:| Step 1: Arrange the x's and y's together. | |
| Step 2: Complete the square for variable x. | |
| Step 3: Complete the square for variable y. | |
| Step 4: Shift constant terms to the RHS. |