Page 208 - Math Skill - 5

206 Maths

2. (a) ∠TOP or ∠POT, Vertex, O, Arms: OT and OP (b) ∠SKY or ∠YKS, Vertex: K, Arms: KS and KY
(c) ∠LMN or ∠NML, Vertex, M, Arms: ML and MN (d) ∠BOA or ∠AOB, Vertex: O, Arms: OB and OA
3. (a) ∠AOC, ∠COB and ∠AOB (b) ∠TPS, ∠SPR, ∠RPQ, ∠TPR, ∠SPQ and ∠TPQ
4. Do it yourself 5. (a) obtuse (b) acute (c) right 6. (a) acute (b) acute
(c) obtuse (d) obtuse (e) reflex (f) right
Exercise 12.2

1. Do it yourself 2. (b), (d) 3. (a), (b) 4. (a) 0° (b) 28° (c) 77° (d) 43° (e) 52°
(f) 9° 5. (a) 43° (b) 162° (c) 1° (d) 77° (e) 97° (f) 69°
Exercise 12.3

1. (a) constant (b) intersect (c) perpendicular (d) perpendicular (e) plane (f) one, one
2. Do it yourself
Exercise 12.4

1. (a) different (b) 60° (c) two, equal (d) greater (e) equal
2. (a) Isosceles (b) scalene (c) scalene (d) equilateral
3. (a) Obtuse-angled triangle (b) right-angled triangle (c) acute-angled triangle
4. (a) 115° (b) 50° (c) 90° 5. 71° 6. 55°, 70° 7. 90°, 50°
8. 70° 40° 9. 60° 10. (a) and (c)
Exercise 12.5

1. (a) OP, OR, OA, OQ and OB (b) PR, AR, ST, AB and PQ (c) AB and PQ
2. (a) chord (b) longest (c) circumference (d) Half 3. Do it yourself
4. (a) 8 cm (b) 10.6 cm (c) 5.4 cm (d) 16.6 cm
5. (a) 3.5 cm (b) 3.4 cm (c) 5.2 cm (d) 6 cm 6. Do it yourself

Assessment Time
A. 1. (b) 2. (a) 3. (a) 4. (b) 5. (a) 6. (c)

B. 1. (a) Acute angle (b) Obtuse angle (c) Straight angle (d) Reflex angle
(e) Complete angle (f) Right angle 2. Diameter 3. Equal
C. 1. PQ, ST 2. No 3. Right angles → < EDC, < DCB, < JIH, < IHG

4. RQ, RP, UT, US, NL, OM 5. < DEF, < EFG, < FGH, < IJA, < JAB, < ABC
D. 1. (d) 2. (c) 3 (a)

CHAPTER - 13: PERIMETER, AREA AND VOLUME

Boot-up 1. B 2. (a) D (b) C (c) A and B 3. 2D, 3D, 3D, 3D

Exercise 13.1
1. (a) 114 cm (b) 13 m (c) 6.75 m 2. (a) 25.6 m (b) 27.2 cm (c) 500 cm
3. B-10 cm, L-50 cm, L-30 cm, B-12 cm, B-24 cm 4. 8 cm, 12 cm, 27 cm, 36 cm, 81 cm

Exercise 13.2
1. (a) 6720 m (b) 1128 cm (c) 100 cm 2 (d) 9750 m 2 2. (a) 25 cm (b) 32 cm (c) 10 cm (d) 58 m
2
2
3. (a) 225 cm (b) 3025 cm (c) 400 cm (d) 324 cm (e) 2916 cm 2
2
2
2
2
4. 3.75 sq. m or 37500 sq. cm 5. 67200 sq. m 6. 6400 sq. m, ` 3200