Solids Chapter Notes | Mathematics Olympiad for Class 1 PDF Download

In geometry, there are various types of solids. Solids are three-dimensional shapes because they have three dimensions such as length, breadth and height. The bodies which occupy space are called solids.

Solid or 3D shapes properties

Solids are classified in terms of their properties. To analyze the characteristics and properties of 3-D geometric shapes, count the number of faces, edges, and vertices in various geometric solids. Let us discuss the properties and formulas for the different solid shapes.

Examples

Q1: Find the total surface area of a cuboid of dimensions 8 cm × 5 cm × 7 cm.
Sol: Given dimensions of a cuboid: 8 cm × 5 cm × 7 cm
That means, length = l = 8 cm
Breadth = b = 5 cm
Height = h = 7 cm
Total surface area of a cuboid = 2(lb + bh + hl)
= 2[8(5) + 5(7) + 7(8)]
= 2(40 + 35 + 56)
= 2 × 131
= 262 cm² 

Q2: Find the volume of the sphere of radius 7 cm.
Sol: Given radius of the sphere = r = 7 cm
Volume of sphere = 4/3 πr³
= (4/3) × (22/7) × 7 × 7 × 7
= 4 × 22 × 7 × 7
= 4312 cm³