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CBSE - VII
Circles
Circles
A circle is defined as a collection of points on a plane that are at an equal distance...
Lesson Demo
Circle:
A circle is defined as a collection of points on a plane that are at an equal distance from a
fixed point on the plane. The fixed point is called the centre of the circle.
Circumference:
The distance around a circular region is known as its circumference.
Diameter:
Any straight line segment that passes through the centre of a circle and whose end points are on the circle is called its diameter.
Radius:
Any line segment from the centre of the circle to its circumference.
Circumference of a circle = 
, where r is the radius of the circle or 
, where d is the diameter of the circle.
Π is an irrational number, whose value is approximately equal to 
.
Circumference = Diameter x 3.14
Diameter(d) is equal to twice radius(r).
Circles with the same centre but different radii are called concentric circles.
