#### Equation for radius of a circle

## What is the formula for finding the radius of a circle?

The two formulas that are useful for finding the radius of a circle are C=2*pi*r and A=pi*r^2. We use algebra skills in solving for our variable r.

## What is the radius of a circle?

The Radius is the distance from the center outwards. The Diameter goes straight across the circle, through the center. The Circumference is the distance once around the circle.

## 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 is the formula for circular?

Formulas Related to Circles

Diameter of a Circle | D = 2 × r |
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Circumference of a Circle | C = 2 × π × r |

Area of a Circle | A = π × r^{2} |

## How do you find the radius of a circle given two points?

Substitute (x1,y1)=(h,k),(x2,y2)=(x,y) and d=r . Square each side. The equation of a circle with center (h,k) and radius r units is (x−h)2+(y−k)2=r2 .

## What is the formula of area?

A = lw (rectangle). That is, the area of the rectangle is the length multiplied by the width. As a special case, as l = w in the case of a square, the area of a square with side length s is given by the formula: A = s^{2} (square).

## What does radius mean?

a straight line extending from the center of a circle or sphere to the circumference or surface: The radius of a circle is half the diameter. the length of such a line. any radial or radiating part.

## Is radius half of diameter?

The radius is half the diameter, or . The diameter of this circle is 36 feet, so the radius is feet. The radius is 18 feet. The distance around a circle is called the circumference.