RS Aggarwal Class 8 Math Nineteenth Chapter Three-Dimensional Figures Exercise 19A Solution
(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.