Lesson Archives

  1. Page No 308: Question 1: Complete the following statements: (i) Probability of an event E + Probability of the event ‘not E’ = _______. (ii) The probability of an event that cannot happen is _________. Such as event is called _________. (iii) The probability of an event that is certain to happen is _________. Such […]
  2. Page No 244: Question 1: 2 cubes each of volume 64 cm3 are joined end to end. Find the surface area of the resulting cuboids. Answer: Given that, Volume of cubes = 64 cm3 (Edge) 3 = 64 Edge = 4 cm If cubes are joined end to end, the dimensions of the resulting cuboid will be 4 […]
  3. Page No 225: Question 1: The radii of two circles are 19 cm and 9 cm respectively. Find the radius of the circle which has circumference equal to the sum of the circumferences of the two circles. Answer: Radius (r1) of 1st circle = 19 cm Radius (r2) or 2nd circle = 9 cm Let the radius […]
  4. Page No 219: Question 1: Draw a line segment of length 7.6 cm and divide it in the ratio 5:8. Measure the two parts. Give the justification of the construction. Answer: A line segment of length 7.6 cm can be divided in the ratio of 5:8 as follows. Step 1 Draw line segment AB of 7.6 […]
  5. Page No 204: Question 1: How many tangents can a circle have? Answer: A circle can have infinite tangents. Question 2: Fill in the blanks: (i) A tangent to a circle intersects it in _______ point (s). (ii) A line intersecting a circle in two points is called a __________. (iii) A circle can have […]
  6. Page No 203: Question 1: A circus artist is climbing a 20 m long rope, which is tightly stretched and tied from the top of a vertical pole to the ground. Find the height of the pole, if the angle made by the rope with the ground level is 30 °. Answer: It can be […]
  7. Page No 181: Question 1: In ΔABC right angled at B, AB = 24 cm, BC = 7 cm. Determine (i) sin A, cos A (ii) sin C, cos C Answer: Applying Pythagoras theorem for ΔABC, we obtain AC2 = AB2 + BC2 = (24 cm)2 + (7 cm)2 = (576 + 49) cm2 = 625 cm2 ∴ […]
  8. Page No 161: Question 1: Find the distance between the following pairs of points: (i) (2, 3), (4, 1) (ii) (−5, 7), (−1, 3) (iii) (a, b), (− a, − b) Answer: (i) Distance between the two points is given by (ii) Distance between is given by (iii) Distance between is given by Question 2: Find the distance between the […]
  9. Page No 122: Question 1: Fill in the blanks using correct word given in the brackets:− (i) All circles are __________. (congruent, similar) (ii) All squares are __________. (similar, congruent) (iii) All __________ triangles are similar. (isosceles, equilateral) (iv) Two polygons of the same number of sides are similar, if (a) their corresponding angles are […]
  10. Page No 99: Question 1: In which of the following situations, does the list of numbers involved make as arithmetic progression and why? (i) The taxi fare after each km when the fare is Rs 15 for the first km and Rs 8 for each additional km. (ii) The amount of air present in a […]