#### Equation of a circle formula

## How do you find the equation of a circle?

The formula for the equation of a circle is (x – h)^{2}+ (y – k)^{2} = r^{2}, where (h, k) represents the coordinates of the center of the circle, and r represents the radius of the circle. If a circle is tangent to the x-axis at (3,0), this means it touches the x-axis at that point.

## What does the equation of a circle tell you?

In fact the equation of a circle is not for finding area, but instead provides an algebraic way to describe a circle. The equation tells you where the center of the circle is in the xy-plane, and what its radius is.

## How do I calculate the area of a circle?

The area of a circle is pi times the radius squared (A = π r²).

## How do you write the standard form of a circle?

The standard form of a circle’s equation is (x-h)² + (y-k)² = r² where (h,k) is the center and r is the radius. To convert an equation to standard form, you can always complete the square separately in x and y.

## How do you find the center and radius of a circle with an equation?

The center-radius form of the circle equation is in the format (x – h)^{2} + (y – k)^{2} = r^{2}, with the center being at the point (h, k) and the radius being “r”. This form of the equation is helpful, since you can easily find the center and the radius.

## What is H and K in a circle?

h and k are just arbitrary letters chosen to represent values in a standard circle equation, Now they are a convention, so everyone usually uses those letters. Circle equation in standard from is: (x-h)^2 + (y-k)^2 = r^2. h and k stand for x and y coordinates of a circle’s center, r is radius.

## What is the center of the circle?

The center of a circle is the point equidistant from the points on the edge. Similarly the center of a sphere is the point equidistant from the points on the surface, and the center of a line segment is the midpoint of the two ends.

## Is a circle a function?

A circle is a set of points in the plane. A function is a mapping from one set to another, so they’re completely different kinds of things, and a circle cannot be a function.

## How do we calculate area?

To find the area of a rectangle, multiply its height by its width. For a square you only need to find the length of one of the sides (as each side is the same length) and then multiply this by itself to find the area.

## Why is the area of a circle πr2?

The height becomes equal to the radius, while the length is half of the circumference (C = 2πR) which now finds itself running along the top and bottom. As the number of triangles “approaches infinity” the circle can be taken apart and rearranged to fit almost perfectly into an “R by πR” box with an area of πR^{2}.