RS Aggarwal Chapter 12 Class 9 Maths Exercises 12.1 (ex 12a) Solutions (Updated for 2024)

RS Aggarwal Chapter 12 Class 9 Maths Exercise 12.1 Solutions: You may have come across many objects in daily life, which are round, such as wheels of a vehicle, bangles, dials of many clocks, coins of denominations 50 p, Re 1 and Rs 5, key rings, buttons of shirts, etc. In a clock, you might have observed that the second’s hand goes around the dial of the clock rapidly, and its tip moves in a round path.

This path traced by the tip of the second’s hand is called a circle. In this chapter, you will study circles, other related terms, and some properties of a circle.

Download RS Aggarwal Chapter 12 Class 9 Maths Exercise 12.1 Solutions

EXERCISE 12A

Access The RS Aggarwal Chapter 12 Class 9 Maths Exercise 12.1 Solutions

Important Definition for RS Aggarwal Chapter 12 Class 9 Maths Ex 12a Solutions

A circle is a closed geometrical figure. All points on the boundary of a circle are equidistant from a fixed point inside the circle (called the centre).

1. Area of a circle (of radius r) = π × r2
2. The diameter of the circle, d = 2 × r
3. Circumference of the circle = 2 × π × r
4. Sector angle of the circle, θ = (180 × l ) / (π × r )
5. Area of the sector = (θ/2) × r2; where θ is the angle between the two radii
6. Area of the circular ring = π × (R2– r2); where R – radius of the outer circle and r – radius of the inner circle