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

We know that the general equation for a circle is ( x – h )^2 + ( y – k )^2 = r^2, where ( h, k ) is the center and r is the radius. So add 21 to both sides to get the constant term to the righthand side of the equation. Then complete the square for the y terms.

## What is the general equation of circle?

The standard equation of a circle with center at ( a , b ) (a,b) (a,b) and radius r r r is ( x − a ) 2 + ( y − b ) 2 (x-a)^2+(y-b)^2 (x−a)2+(y−b)2= r 2 r^2 r2. If we have a point O = ( a , b ) O=(a,b) O=(a,b) in the plane and a radius r r r, then we can construct a unique circle.

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

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

## 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.

### Releated

#### Foci equation

How do you find foci? actually an ellipse is determine by its foci. But if you want to determine the foci you can use the lengths of the major and minor axes to find its coordinates. Lets call half the length of the major axis a and of the minor axis b. Then the distance […]

#### Steady state concentration equation

What is the steady state concentration? Steady-state concentration (Css) occurs when the amount of a drug being absorbed is the same amount that’s being cleared from the body when the drug is given continuously or repeatedly. Steady-state concentration is the time during which the concentration of the drug in the body stays consistent. How long […]