Page 236 - Maths Skills - 7

234 Maths

Assessment Time
A. 1. (i) 2. (iv) 3. (iv) 4. (iii) 5. (ii) B. 1. line/axis of symmetry 2. square 3. two
4. point symmetry 5. dimensions and angle C. 1. F 2. T 3. F
D. 1. The given figures only has a vertical line of symmetry. 2. 3.

4. A line that divides the object into its identical halves is known as a line of a symmetry.
E. 1. (d) 2. (d) 3. (c) F. Do yourself.
G. (a) Yes, it has 6 lines of symmetry (b) Yes (c) Centre of this figure (d) Order = 6 (e) 60°

HOTS

1. Only line symmetry: A, B, C; Only rotational symmetry: N, S, Z
2. Yes, two or more lines of symmetry implies rotational symmetry. For example letters H, I, O have 2 lines of symmetry hence rotational symmetry
as well. No for example a parallelogram has rotational symmetry but no line symmetry.
3. (i) rotation (ii) rotation (iii) reflection (iv) rotation

Chapter - 12: Data Handling
Boot-up

A. 1. (i) 2. (ii) 3. (ii) 4. (iii) B. 1. frequency 2. array 3. horizontal 4. difference
C. 1. T 2. F 3. T 4. T

Exercise - 12.1
1. 142 cm 2. Mean–5376.67 3. Mean–68.33, Median–72.5, Mode–78 4. (i) Median–6, Mode–6
(ii) Median–19, Mode–19 5. (i) 5.5 (ii) 8 (iii) 6.83 6. Mean–3.86, Median–4, Mode–6
7. 1564 8. Mode–20, Mean–16.86, Median–19 9. 48 kg 10. 29.75

Exercise - 12.2
1. (i) Bar graph shows the number of vehicles passing through a particular road crossing
(ii) 9 to 10 a.m. ; 400 vehicles (iii) 12 noon to 1 p.m. ; 150 vehicles (iv) 2520 vehicles
2. (i) 50 students (ii) 35 students (iii) 205 students (iv) class IX (v) class VI and class VIII
3. (i) Bar graph shows the number of newspapers published in 8 languages (ii) 11700 newspapers
69
(iii) 1300 newspapers (iv) 21 %
211
4. (i) Bar graph shows the production of cloth in various years in a textile mill.
(ii) 6 years (iii) 2000 (iv) 1997 (v) 11 : 4 [5., 6., 7. & 8. Do it yourself.]
Assessment Time

A. 1. (iv) 2. (iii) 3. (iv) 4. (ii) 5. (ii)
Sum of observations
B. 1. mode 2. 3. Highest value – Lowest value 4. numerical
Total number of observations
C. 1. T 2. F 3. T 4. F 5. T D. 1. (ii) 2. (i) 3. (iii) 4. (iv)
E. 1. (a) 2. (a) 3. (c) F. 1. 1564 2. 61 marks 3. 30 4. 20.2, 21, 19
5. Mean = ` 551.75; Median = ` 600.50; Mode = ` 700
6. (i) 51 (ii) ` 80.80 (iii) ` 62, ` 80 G. (a) 2.01 inches (b) 6.04 inches