EXERCISE 19A

(1) Write down the number of faces of each of the following figures:

(i) Cuboid = 6 faces

(ii) Cube = 6 faces

(iii) Triangular prism = 5 faces (2 triangular and 3 rectangular)

(iv) Square pyramid = 5 faces (1 sq. faces and 4 triangular faces)

(v) Tetrahedron = 4 triangular faces

(2) Write down the number of edges of each of the following figures:

(i) Tetrahedron = 6 edges

(ii) Rectangular pyramid = 8 edges

(iii) Cube = 12 edges

(iv) Triangular prism = 9 edges

(3) Write down the number of vertices of each of the following figures:

(i) Cuboid = 8 vertices

(ii) Square pyramid = 5 vertices

(iii) Tetrahedron = 4 vertices

(iv) Triangular prism = 6 vertices

(4) Fill in the blanks:

(i) A cube has 8 vertices, 12 edges and 6.

(ii) The point at which three faces of a figure meet is known as its vertex.

(iii) A cuboid is also known as a rectangular cube.

(iv) A triangular pyramid is called a tetrahedron.