Page 389 - Start Up Mathematics_8 (Non CCE)

Exemplar Problems Solve Mentally
1. a 2. b 3. Square 4. True Match the Columns
5. 2 : 1 6. 90° 7. Yes (a) (v) (b) (i) (c) (iv) (d) (ii) (e) (iii)
Answer in One Word or a Line
Chapter 15
1. (a) Cube → Dice, rubik cube, etc.
Review Exercises (b) Cuboid → Pencil box, book, etc.
Multiple Choice Questions (c) Cylinder → Gas cylinder, softdrink can, etc.
1. b 2. c 3. a 4. b 5. c (d) Prism → Scientific glass prism
(e) Pyramid → Pyramid in Egypt
Solve Mentally 2. Yes, if the number of faces is four or more.
True or False 3. Yes
1. True 2. False 3. False 4. False 5. True 4. If in any polyhedron, the line segment joining any two
points on its surface lie entirely inside or on the polyhedron,
Answer in One Word or a Line a polyhedron is called a convex polyhedron.
1. No 5. If the bases of a quadrilateral prism are parallelograms, it
2. Yes, because all the sides of a rhombus are equal. is called a parallelepiped.
3. Kite, rhombus 6. In a platonic solid,
4. Yes. The opposite sides of a parallelogram are equal.
(i) at least three faces meet at a vertex to form a solid
Exemplar Problems angle.
1. b 2. c 3. 2 included (ii) the sum of all plane angles forming the solid angle
4. False 5. True at a vertex is less than 360º.
6. Students to do on their own. 7. Octahedron: F = 8, V = 6, E = 12
7. Student to do on their own. Icosahedron: F = 20, V = 12, E = 30
8. Student to do on their own. Dodecahedron: F = 12, V = 20, E = 30
9. Student to do on their own. Let’s Evaluate
10. Student to do on their own. 1. 22

Chapter 16 4. (a) (b)
Exercise 16.1
1. (i) 8 vertices (ii) 5 faces (iii) 12 edges (iv) 20 faces
(v) 5 vertices
3. (a) A cylinder and cuboid (b) Two cones (c)
(c) Half cylinder and cuboid (d) Cube and cone
(e) Hemisphere and cylinder (f) Two cylinders
4. (a) Square pyramid (b) Triangular prism
(c) Regular tetrahedron (d) Octagonal prism 5. (a) (i) Side (ii) Front (iii) Top
(e) Hexagonal pyramid (b) (i) Top (ii) Side (iii) Front
Exercise 16.2 (c) (i) Front (ii) Top (iii) Side
1. (a) (i) Side (ii) Top (iii) Front 6. 4.5 cm
(b) (i) Front (ii) Top (iii) Side Thinking Skills
(c) (i) Front (ii) Top (iii) Side 1. (a) Rectangular pyramid (b) Hexagonal pyramid
(d) (i) Top (ii) Front (iii) Side (c) Hexagonal prism (d) Cube
(e) (i) Front (ii) Side (iii) Top 2. a 3. (a) and (d)
2. (a) — (iv) (b) — (i) Exemplar Problems
(c) — (ii) (d) — (iii) 1. c 2. b 3. 7 4. False
Review Exercises
Multiple Choice Questions 5. False 6. Yes;
1. a 2. b 3. d
4. c 5. d 6. a
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