Page 353 - Start Up Mathematics_7

7. Symbol Number of Number of Chapter 11
digits segments 1. ∠A ↔ ∠F, ∠B ↔ ∠E, ∠C ↔ ∠D;
5 26 AB ↔ FE, BC ↔ ED, AC ↔ FD
10 51
100 501 2. (i) ∠C (ii) CA (iii) ∠A (iv) BA
5 16 3. (a) SSS Congruence criterion
10 31 (b) SAS Congruence criterion
100 301 (c) ASA Congruence criterion
5 27
10 52 (d) RHS Congruence criterion
100 502 4. (a) (i) PE (ii) EN (iii) PN (b) (i) EN (ii) AT

Chapter 7 Chapter 12
1. (a) No (b) No (c) Yes (d) No (e) No (f) No Students to do on their own.
2. (i) p = 3 (ii) m = 6
3. (a) Step 1: Add 2 to both sides Chapter 13
Step 2: Divide both sides by 3; n = 16
(b) Step 1: Subtract 7 from both sides 1. (a) (b)
Step 2: Divide both sides by 5; m = 2
(c) Step 1: Multiply both sides by 3
Step 2: Divide both sides by 20; p = 6 (c) (d)
(d) Step 1: Multiply both sides by 10
Step 2: Divide both sides by 3; p = 20
4. (a) x = 2 (b) n = 12 (c) n = –2 (d) x = –4 (e) x = 0
Chapter 8 (e) (f)
1. 12 Computers
2. (i) Rajasthan: 190 people; UP: 830 people (ii) Rajasthan
3. 30% 4. ` 4,000 5. 2% 6. ` 16,875
7. (a) ` 1,632 (b) ` 8,625 8. 0.25% 2. (a) 3 (b) 6 (c) 5 (d) 4 3. Yes
4. Square 5. 120°, 180°, 240°, 300°, 360°
Chapter 9
Chapter 14
1. (a) supplementary (b) complementary
2
(c) supplementary (d) supplementary 1. 15 cm, 525 cm 2. 40 m 3. 31 cm, square
(e) complementary (f) complementary 4. (a) 12.3 cm (b) 10.3 cm (c) 5.8 cm (d) 1.05 cm
2. 45° 3. 90° 5. (a) 11.6 cm (b) 80 cm (c) 15.5 cm
2
4. ∠1 and ∠2 are not adjacent angles because their vertex 6. Area of ∆ABC = 27 cm ; length of CE = 7.2 cm
2
is not common. 7. 132 m, ` 528 8. 536 cm 9. 30 cm 2
5. a = 55°, b = 125°, x = 55°, d = 125°, e = 55°, f = 55°
6. (a) ∠DGC = 70° (b) ∠DEF = 70° Chapter 15
7. Students to do on their own.
1. Three faces
Chapter 10
1. (i) 65° (ii) 30° (iii) 35° (iv) 60° (v) 50° (vi) 40°
2. (i) x = 70°, y = 60° (ii) x = 50°, y = 80° 2. Students to do on their own.
(iii) x = 110°, y = 70° (iv) x = 60°, y = 90° 3. Students to do on their own.
(v) x = 45°, y = 90° (vi) x = 60°, y = 60° 4. Students to do on their own.
3. Between 3 and 27 4. 9 m 5. 18 m 5. Students to do on their own.

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