# Mensuration – Exercise 4.6.2 – Class IX

1. Draw 2D diagram of the following :

(a) Rectangle- based prism:

(b) Square – based prism:

(c) Square – based pyramid:

(d) Tetrahedron: (triangular pyramid)

(e) Square – based oblique prism:

(f) Square – based oblique pyramid:

(g) Triangular – based oblique prism:

Solution:

(a) (b) (c) (d) (e) (f) (g) 1. Differentiate between

(a) Right prism and oblique prism.

(b) Height and slant height of a pyramid.

(c) Prism and pyramid.

Solution:

 (a) Right prism oblique prism Right prism are prism whose lateral edges are perpendicular to the base . prism is a prism whose lateral edges are not perpendicular to the base. (b) Height of a pyramid slant height of a pyramid. The perpendicular distance between the base and vertex of the pyramid is height of pyramid (h) The perpendicular distance between vertex of pyramid to the edge of the base is slant height (L) (c) Prism pyramid. Prism is a solid which has 2 base. Pyramid is a solid which has only 1 base.

1. Classify the following solids in to regular and irregular prisms:

(a) Rectangular based prism

(b) Equilateral triangle based prism

(c) Square based prism

(d) Cude

(e) Right triangle based prism

(f) Scalene triangle based prism

Solution:

(a) Rectangular based prism – irregular prism.

(b) Equilateral triangle based prism – regular prism.

(c) Square based prism – regular prism.

(d) Cude – regular prism.

(e) Right triangle based prism – regular prism.

(f) Scalene triangle based prism – irregular prism.