Chapter 12 Exponents and Powers Exercise 12.2
Chapter 12 Exponents and Powers Exercise 12.2 Question 1. Express the following numbers in standard form: (i) 0.0000000000085 (ii) 0.00000000000942 (iii) 6020000000000000 (iv) 0.00000000837 (v) 31860000000 Solution: (v) 31860000000 = 3.186 × 10000000000 = 3.186 × 1010 Hence, the required standard from = 3.186 × 1010 Question 2. Express the following numbers in usual form. […]
Chapter 12 Exponents and Powers Exercise 12.1
Chapter 12 Exponents and Powers Exercise 12.1 Question 1. Evaluate: Solution: Question 2. Simplify and express the result in power notation with a positive exponent. Solution: Question 3. Find the value of Solution: Question 4. Solution: Question 5. Find the value of m for which 5m ÷ 5-3 = 55. Solution: 5m ÷ 5-3 = 55 ⇒ 5m-(-3) = 55 [∵ […]
Chapter 11 Mensuration
Chapter 11 Mensuration Very Short Answer Type Question 1. Find the perimeter of the following figures: So, the circle will have a larger area. Question 4. The length and breadth of a rectangle are in the ratio 4 : 3. If its perimeter is 154 cm, find its length and breadth. Solution: Let the length […]
Chapter 11 Mensuration Exercise 11.4
Chapter 11 Mensuration Exercise 11.4 Question 1. Given a cylindrical tank, in which situation will you find the surface area and in which situation volume. (a) To find how much it can hold. (b) Number of cement bags required to plaster it. (c) To find the number of smaller tanks that can be filled with […]
Chapter 11 Mensuration Exercise 11.3
Chapter 11 Mensuration Exercise 11.3 Question 1. There are two cuboidal boxes as shown in the figure. Which box requires the lesser amount of material to make? Solution: (a) Volume of the cuboid = l × b × h = 60 × 40 × 50 = 120000 cm3 (b) Volume of cube = (Side)3 = (50)3 = […]
Chapter 11 Mensuration Exercise 11.2
Chapter 11 Mensuration Exercise 11.2 Question 1. The shape of the top surface of a table is a trapezium. Find its area if its parallel sides are 1 m and 1.2 m and perpendicular distance between them is 0.8 m. Solution: Question 3. Length of the fence of a trapezium-shaped field ABCD is 120 m. […]
Chapter 11 Mensuration Exercise 11.1
Chapter 11 Mensuration Exercise 11.1 Question 1. A square and a rectangular field with measurements as given in the figure have the same perimeter. Which field has a larger area? Solution: Perimeter of figure (a) = 4 × side = 4 × 60 = 240 m Perimeter of figure (b) = 2 [l + b] […]
Chapter 10 Visualising Solid Shapes
Chapter 10 Visualising Solid Shapes Very Short Answer Type Question 1. Draw any four 3-dimensional figures. Solution: Question 2. Verify Euler’s formula for a right triangular prism. Solution: Number of vertices (V) = 6 Number of faces (F) = 5 and number of edges (E) = 9 Euler’s formula: V + F – E = […]
Chapter 10 Visualising Solid Shapes Exercise 10.3
Chapter 10 Visualising Solid Shapes Exercise 10.3 Question 1. Can a polyhedron have for its faces (i) 3 triangles? (ii) 4 triangles? (iii) a square and four triangles? Solution: (i) No, because polyhedron must have edges meeting at vertices which are points. (ii) Yes, because all the edges are meeting at the vertices. (iii) Yes, […]
Chapter 10 Visualising Solid Shapes Exercise 10.2
Chapter 10 Visualising Solid Shapes Exercise 10.2 Question 1. Look at the given map of a city. Answer the following. (a) Colour the map as follows: Blue-water, red- fire station, orange-library, yellow-schools, Green-park, Pink-College, Purple-Hospital, Brown-Cemetery. (b) Mark a green ‘X’ at the intersection of Road ‘C’ and Nehru Road, Green ‘Y’ at the intersection […]