Page 263 - Start Up Mathematics_8 (Non CCE)

3. A triangular pyramid is called a:
(a) prism (b) hexahedron (c) icosahedron (d) tetrahedron
4. A solid having 5 faces, 5 vertices and 8 edges is a:

(a) cube (b) cuboid (c) square pyramid (d) tetrahedron
5. Each face of an icosahedron is:
(a) a pentagon (b) a square (c) a hexagon (d) an equilateral triangle
6. The number of vertices in an octagonal pyramid are:
(a) 9 (b) 10 (c) 8 (d) 6

solve Mentally

Match the Columns:
Column A Column B
(a) Octagonal pyramid (i) 8 vertices
(b) Cube (ii) 30 edges
(c) Hexagonal prism (iii) 12 faces
(d) Icosahedron (iv) 12 vertices
(e) Dodecahedron (v) 9 faces

Answer in One Word or a Line

1. Give examples of each of the following shapes from your surroundings:
(a) cube (b) cuboid (c) cylinder (d) prism (e) pyramid
2. Is it possible to have a polyhedron with any given number of faces?
3. Is a square prism same as a cube?
4. Define a convex polyhedron.
5. What is parallelepiped?
6. What are the properties of a platonic solid?
7. Give the number of faces, vertices and edges of an octahedron, icosahedron and dodecahedron.

let’s evaluate
1. A solid has 40 faces and 60 edges. How many vertices will it have?
2. Draw nets of cube and triangular prism.
3. Draw a nested solid consisting of:
(a) a cube and a hemisphere (b) a cube and a cuboid

(c) a cylinder and a cone (d) a cone and a hemisphere
(e) two cones (f) two different cubes
4. Add the face that is needed to make the net of:
(a) a square prism (b) a cylinder (c) a rectangular prism

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