# Circle Tutorial

## Circle Tutorial

##### Circle Definition:

A circle is the set of all points in a plane at a fixed distance, called the radius, from a given point, the center.

#### Circle Formula:

Area of Circle = πr² Diameter of Circle = 2r Circumference of Circle = 2 πr = πd Area of Sector = πr² θ/360)
##### Circle Image/Diagram ##### Case 1:

Find the area, diameter and circumference of a circle with the given radius 3.

###### Step 1:

Find the area. Area = πr² = 3.14 * 3² = 3.14 * 9 = 28.26.

###### Step 2:

Find the diameter. Diameter = 2r = 2 * 3 = 6.

###### Step 3:

Find the circumference. Circumference = πd = 3.14 * 6 = 18.84.

##### Case 2:

Find the area of sector with the given radius 3 and theta 30.

###### Step 1:

Find the area. Area =πr² θ/360) = 3.14 * 3² * (30/360) = 3.14 * 9 * 0.083 = 2.35. The above example will clearly illustrates how to calculate the Area, Diameter and Circumference of a Circle, Area of Sector manually.

#### Related Calculator:

This tutorial will help you dynamically to find the Math area problems.