Geometry is a very important part of mathematics in which lines and circles play a very crucial role. A circle is more an ellipse, it has two foci that are coincident with an eccentricity of zero. A line has a locus of a point that is in a constant direction whereas in a circle the locus of a point is moving in a constant direction starting from a fixed point.

What is a Circle?

The circle is mainly a collection of multiple points on the plane, which are at a fixed distance from each other from the fixed point. Consider the centre of the circle as ‘O’. It is a closed curve that is traced on all the fixed points on an equidistant.

This closed curve circle is divided into two regions which are interior and exterior. The term ‘circle’ can be used interchangeably for interior and exterior collectively.

A circle is only a boundary but a circle with a whole figure is called a disc. According to Euclid, a circle is mainly a simple plane figure which is bounded by a single curved line such that all the lines are drawn from a certain point within a single bounded line and that are equal.

Properties of a Circles

The circle is a crucial part of geometry, that is why there are several properties of the circle to remember. Given below are the important circle properties.

• The diameter of the circle is the longest chord in any circle.
• Two circles are said to be congruent if they have an equal radius.
• If the radius is drawn perpendicular to the chord, then that chord is bisected.
• The circles with different radii are considered similar.
• A circle can be inscribed in a square and triangle.
• A circle can be circumscribed in a rectangle, triangle, square, and also in a trapezoid.
• The distance between the circle of the circle to the longest diameter is zero.
• Tangents drawn on both ends of the diameter are parallel to each other.
• When the radii are joined to the end of the chords to the center of the circle then the triangle is considered as Isosceles.
• If the perpendicular distance from the circle is decreased, then the length of the chord drawn increases.

Terminologies of a Circle.

After the important properties of a circle comes the important terminologies in a circle which is given below:

1. Centre: It is a fixed point inside the circle that is equidistant from every point on the boundary of the circle.
2. Radius: It is the fixed distance between the centre of the circle and the points fixed on the boundary of the circle.
3. Chord: It is a line portion that connects two points on the boundary of the circle without touching the centre of the circle.
4. Diameter:  It is referred to as a chord of the circle that passes through the centre of the circle. There can be an infinite number of diameters in a circle.
5. Secant:  When a chord intersects the circle in two points is referred to as a secant.
6. Tangent: When any line touches any point of the circle at any point with intersecting the circle then that is referred to as the tangent to that circle.
7. Arc:  It is a part between the boundary of the circle between any two points.
8. Circumference: The length of the boundary of any given circle is referred to as the circumference of that circle.
9. Sector: The region between the arc of the circle and any two radii is called the Secret of the circle.
10. Segment: The region between the chord in a circle and the arc of the circle is the segment of the Circle.

Conclusion

Circles, as mentioned above, are a very important part of geometry and Mathematics as a whole. Concepts of circles are used in different parts of our lives for instance, in the field of architecture and in the field of construction too. A circle is a two-dimensional figure which is defined as the collection of all the points that are present on a plane that is equidistant from any given point. The FAQs section provides additional information which will aid a better understanding of the topic.