New NCERT Books

NCERT Class 9 Maths Ganita Manjari Chapter 12 Solutions NCERT Class 9 Maths Ganita Manjari Chapter 12 Exercise Set 12.1 1. Let ABCD be a quadrilateral.  (i) List all sides of ABCD adjacent to side AB. List all sides opposite to AB. (ii) List all angles of ABCD adjacent to ∠A. List all angles opposite to ∠A. (iii) Define a pair of opposite sides and a pair of opposite angles without using the names of the vertices. Answer:  1. Let ABCD be a quadrilateral.   (i) List all sides of ABCD adjacent to side AB. List all sides opposite to AB. The sides adjacent to AB are AD and BC . The side opposite to AB is CD . (ii) List all angles of ABCD adjacent to ∠A. List all angles opposite to ∠A. The angles adjacent to ∠A are ∠B and ∠D . The angle opposite to ∠A is ∠C . (iii) Define a pair of opposite sides and a pair of opposite angles without using the names of the vertices. A pair of opposite sides of a quadrilateral are two sides that do not share a common vertex. A pair of op...

Class 09  | Ganita Manjari 02 | Ch. 14  Maths of Space: Surface Area and Volume |  NCERT Solutions Think and Reflect (Page 124) Q. Try to work out for yourself why this model explains the formula for the volume of a cuboid, i.e., volume = area of base × height. Write the formula for the surface area and the volume of a cube. Solution: A cuboid can be considered as a stack of thin rectangular pieces, each of length l and width w and area lw. Adding the volumes of all the pieces up to height (h) gives the volume of the cuboid. Volume of a cuboid = l × w × h Thus, Volume = Area of base × Height (i) For a cube with side a, Surface area of a cube = 6a 2 Volume of a cube = a 3 Learn Math Exercise Set 14.1 (Page 125 – 126) 1. The volume of a cube is 64 cm 3 . What is its total surface area? Solution: Let the side of a cube be ‘a’ cm. Volume of cube = 64 cm 3 ⇒ a 3 = 64 ⇒ a = = 4 cm Total surface area = 6a 2 = 6(4) 2 = 6 × 16 = 96 cm 2 . Therefore, total surface area of cube ...

Class 09  | Ganita Manjari 02 | Ch. 11  The World Of Alogrithms |  NCERT Solutions Exercise 11.1 1. Add two 4 digit numbers using the steps we have written down. Make sure you follow the steps precisely; do not perform any action that is not explicitly mentioned. Are you able to obtain the correct result? Solution: Let us add 5493 and 2658. Number Addition Steps Step 1: Write the numbers one below the other, aligning the digits from right to left. Step 2: Add the ones: 3 + 8 = 11. Write 1 and carry 1. Step 3: Add the tens: 9 + 5 + 1(carry) = 15. Write 5 and carry 1. Step 4: Add the hundreds: 4 + 6 + 1(carry) = 11. Write 1 and carry 1. Step 5: Add the thousands: 5 + 2 + 1(carry) = 8. Write 8 and carry 0. Thus, the result is 8151, which is correct. 2. What happens if you add a 5-digit number to a 3-digit number. Do our steps handle this situation correctly? Solution: The steps to add two numbers do not handle this situation correctly because it does not explain what to do...

Class 09  | Ganita Manjari 02 | Ch. 13  Two Variables, One Line |  NCERT Solutions Exercise Set 13.1 (Page 87) 1. Write a linear equation in two variables in which a = 3, b = 0 and c = – 1 5 . Solution: The standard form of linear equation is ax + by + c = 0. Using a = 3, b = 0 and c = – 1 5 , 3x + 0(y) + ( − 1 5 ) = 0 3x – 1 5 = 0 Hence, the required linear equation is 3x – 1 5 = 0. Linear equation solver 2. Complete the following table after expressing the given linear equations in standard form. Solution: 3. (i) The cost of a notebook is twice the cost of a pen. Consider the cost of a notebook to be ₹t and that of a pen to be ₹p. Charlie wrote t = 2p , whereas Meera wrote p = 2t. Which of these two representations is correct? Solution: Let the cost of a notebook to be ₹t and that of a pen to be ₹p. Since the cost of a notebook is twice the cost of a pen. Therefore, t = 2p Hence, Charlie’s representation is correct. (ii) In a one-day International Cricket match bet...