Page 177 - Maths Skills - 8

Mensuration 175

18. Find the area of each of the following field. All dimensions are in metres.

(i) (ii)

F

SOLIDS
Solids don't lie wholly in a plane since they have three dimensions—length, breadth and height. They are called
three dimensional figures. And we shall also learn how to find the surface area and the volume of a cuboid, a cube
and a cylinder.

Cube
If the length, breadth and height of a solid shape are equal, that solid is called a cube.

For example; a dice, an ice cube, a sugar cube, etc. Each edge of a cube is called its side.

Cuboid
A cuboid is a solid bounded by six rectangular faces.
h
For example; a box, a book, a brick, a matchbox, etc.
Consider the adjoining Fig., which shows a cuboid. l

Faces of a Cuboid
A cuboid has 6 rectangular faces.
These faces are: ABCD, HGFE, AHED, BGFC, EFCD and HGBA.

Edges of a Cuboid

The two adjacent faces meet in a line segment, called an edge of the cuboid. Every cuboid has 12 edges.
The edges of the given cuboid are AB, BC, CD, DA, HG, GF, FE, EH, AH, ED, BG and FC.

Vertices of a Cuboid
The point where three edges of a cuboid meet is called a vertex. Every cuboid has 8 vertices.

The vertices of the given figure are A, B, C, D, E, F, G and H.
Base and Lateral Faces of A Cuboid
The bottom face of a cuboid is called the base of a cuboid. The four faces which meet the base are called lateral
faces of the cuboid.

In Fig., EFCD is the base and ABCD, BGFC, HGFE, AHED are its lateral faces.