Page 238 - Maths Skills - 7

236 Maths

HOTS
1. (i) Sachin’s average of 55 is better than that of Sameer’s 54. (ii) Median score of Sachin is 55 which is greater than that of Samir’s 50.
2. (i) Mean = 152.05 (ii) Median = 150 (iii) Mode = 142
3. (i) Type of refreshment Frequency (ii) Do it yourself.
Juice 4
Ice cream 11
Chocolate 7
Cold drink 9
Coffee 5
Total 36

(iii) Ice-cream is liked by maximum students (iv) No as the data is not continuous

Chapter - 13 Visualising Solid Shapes
Boot-up

A. 1. (ii) 2. (iii) 3. (i) 4. (iv) B. 1. cube 2. sphere 3. 8 4. solid
C. 1. T 2. F 3. T 4. F

Exercise - 13.1
1. (i) cuboid (ii) cube (iii) cone (iv) sphere (v) triangular prism (vi) cylinder (vii) Rectangular pyramid
(viii) hemisphere 2. (i) – (c), (ii) – (a), (iii) – (d), (iv) – (b) 3. Do it yourself. 4. (i)
5. Do it yourself. 6. (iii) 7. Triangular Prism 8. (i) and (iii)

Assessment Time
A. 1. (ii) 2. (i) 3. (ii) 4. (ii) 5. (iv) B. 1. cube 2. 3, 6 3. net
4. triangular 5. cube C. 1. F 2. F 3. T 4. F 5. T
D. 1. (iii) 2. (i) 3. (iii) 4. (ii) 5. (i) E. 1. (a) 2. (a) F. Do yourself.

HOTS

1. If, F = faces, V = vertices, E = edges of a polyhedron, then F + V = E + 2
For an icosahedron, number of edges n is
n = F + V – 2 = 20 + 12 – 2 = 30
2. The front, top and side view of an object is its 2-D sketch as seen from front, side or top. An object having all three views identical is a sphere.
3. Prism Diagonal per vertex Total number of diagonals 4. Do it yourself
Quadrilateral 1 4
Pentagonal 2 10
Hexagonal 3 18
Assessment - 4

1. (c) 2. (d) 3. (a) 4. (b) 5. (c) 6. 1 7. 3
 n +  1 th Sum of all observations
8. Upper value – lower value 9.   value 10. 11. (T) 12. (T)
 2  No. of observations
13. (T) 14. (T) 15. (T) 16. Pyramid 17. Square 18. 4 19. (i) 20. (a)
21. (a) 22. Do yourself 23. Do yourself
24. Median = 35, Range = 20 25. 4.75 26. x = 19