Page 109 - ICSE Math 4

Geometry
9 Geometry

Learning Outcomes

Students will be able to learn:
 basic concepts of geometry.
 about intersecting, perpendicular and parallel lines.
 about circle and its parts.
 the relation between diameter and radius of a circle.
 perspectives of shapes: plan, elevation and side view.
 about tangram and tessellation.
 about symmetry and refl ection symmetry.

Geometry is a branch of mathema cs that deals with points, lines, shapes and solids. We
have already learnt about shapes and solids. Let’s revise them quickly and learn more
about geometry in this chapter.

Basics of Geometry

There are some basic concepts and terms that we need to know in geometry. These include
plane, point, line, line segment and ray.

Plane

A plane is a flat smooth surface which extends indefi nitely in all the direc ons. It has only

two dimensions, i.e., length and breadth. Walls, fl oors and table tops are some examples
of plane.
Top Tip
Point
All geometrical
A point is just a dot made on paper which shows the actual fi gures are made of
posi on marked by a pencil, pen or a marker. It does not points.
have any shape, size, length, breadth or thickness. It is the
smallest geometrical shape and is denoted by capital le ers such as A, B and C.
• • •
A B C

Line

A line has no star ng point or ending point and thus, it cannot be measured. It can be
extended up to any length in both the direc ons.
N

A line MN is wri en as MN or NM with arrowheads on both the sides.
M
99