Circles Class 9th Notes - Free NCERT Class 9 Maths Chapter 10 Notes - Download PDF

# Circles Class 9th Notes - Free NCERT Class 9 Maths Chapter 10 Notes - Download PDF

Edited By Ramraj Saini | Updated on Apr 21, 2022 02:01 PM IST

## Class 9 maths chapter 10 notes

Circles are one of the important chapters in the Class 9 Maths subject. Circles class 9 notes deal with the basic details of the circle and the terms associated with it. It will help students by acting as a quick revision material before going to appear for the examination. CBSE class 9 maths chapter 10 notes also help students in getting good marks in the Board examination. Class 9th maths chapter 10 notes also contain the important theorems of circles. Class 9 maths chapter 10 notes also help students in giving key points for several competitive examinations.

Also, students can refer,

## NCERT notes for class 9 maths chapter 10

Circles

The circle is a shape or geometry in which a set of all the points is fixed in a plane at a fixed distance and starts from a fixed point. The fixed point from which the set of points is at a fixed distance is the center of the circle. There are three parts in which a circle divides the plane one is the interior and the second part is the circle itself and the third part is the exterior.

One of the terms associated with the circle in which it can be defined as the distance between the central point of a circle and any point on a given circle.

Tangent

In the circle, if a line touches the circle on exactly one point is the tangent.

Secant

In the circle, if a line touches or cuts the circle in two points is secant.

Chord

A chord is a line segment that is present within the circle in which it is joining two points on the circle.

Diameter

It is the straight line whose either end touches the circle and passes through the center of the circle. The value of the diameter is twice the value of radius and it can also be called the longest chord.

Arc

Arc is the section of the circumference of the circle. The longest portion is the major ARC and the shortest is the minor Arc if two pieces of arc are made.

Here AB is the arc.

Circumference

In a circle the distance covered by going around its surface is the perimeter and the name of the perimeter when it comes to the circle is the circumference. And its equation is 2πr.

Semicircle

In a circle of diameter parts, the circle into two equal parts, and the two equal parts are called an arc. Under these two arcs given the name is a semicircle.

Congruent Circles

When two circles can be superimposed on the other so it will cover exactly equal then it is said to be congruent.

Segment

When a circle is cut by a secant or a chord the circular segment is formed. and there among which the smaller region is the minor segment and the bigger one is the major segment.

Sector

An arc plus two radii together is known as the sector. In which the minor portion is called the minor sector and the major portion is called the major sector.

A quadrilateral ABCD can be said to be a cyclic quadrilateral if and only if all the four vertices of it lie on a circle.

## Important Theorems

• For a circle, if the two arcs are said to be congruent then their corresponding chords are equal.

• For the same segment of a circle, the angle is equal.

• The sum of the opposite angles of a circle is 180°.

• For a semicircle, the angle present on them is 90°.

• For a circle, if the two chords of which are equal then their corresponding arcs that are major or minor or semi-circle are congruent.

• In a semicircle, the angle is the right angle.

• The exterior angle is the same as that of the interior opposite angle in a cyclic quadrilateral.

• A quadrilateral is cyclic if the sum of opposite angles is 180°.

• From one point an infinite number of circles can be made.

## Significance of NCERT notes for class 9 maths chapter 10

NCERT notes for class 9 maths chapter 10 covers the important concepts regarding the circles. This note helps students to get qualified in the VITEEE, BITSAT, JEE Main, NEET , and other competitive examinations. Notes for class 9 maths chapter 10 also provide quick revision for students before going to the examination. As this note covers important sections of circles it will help students in getting good marks in the CBSE examination. Class 9 maths chapter 10 notes pdf download enable students to learn in the offline mode also.

NCERT solutions of class 9 subject wise

NCERT Class 9 Exemplar Solutions for Other Subjects:

NCERT Class 9 Notes Chapter wise

 NCERT Class 9th Math Chapter 1 Notes NCERT Class 9th Maths Chapter 2 Notes NCERT Class 9th Maths Chapter 3 Notes NCERT Class 9th Maths Chapter 4 Notes NCERT Class 9th Maths Chapter 5 Notes NCERT Class 9th Maths Chapter 6 Notes NCERT Class 9th Maths Chapter 7 Notes NCERT Class 9th Maths Chapter 8 Notes NCERT Class 9th Maths Chapter 9 Notes NCERT Class 9th Maths Chapter 10 Notes NCERT Class 9th Maths Chapter 11 Notes NCERT Class 9th Maths Chapter 12 Notes NCERT Class 9th Maths Chapter 13 Notes NCERT Class 9th Maths Chapter 14 Notes NCERT Class 9th Maths Chapter 15 Notes

1. What is the angle made by a semicircle?

Right angle.

2. What is the constant distance on a circle called?

Radius. It is also mentioned in the class 9 Circles notes.

3. How many parts does a circle divide the plane?

Three parts. This is explained in detail in the class 9 Maths Chapter 10 notes.

4. Give the relationship between diameter and radius?

Diameter=2r

5. What is the name of a line formed between two points in a circle?

Chord. It is given in detail in the Circles class 9 notes pdf download/NCERT class 9 maths chapter 10 notes.

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