NCERT Book Class 9 Maths Chapter 5 Introduction to EUCLID's Geometry

60 MATHEMATICS

CHAPTER 5

INTRODUCTION TO EUCLID’S GEOMETRY

5.1 Introduction
The word ‘geometry’ comes form the Greek words ‘geo’, meaning the ‘earth’,
and ‘metrein’, meaning ‘to measure’. Geometry appears to have originated from
the need for measuring land. This branch of mathematics was studied in various
forms in every ancient civilisation, be it in Egypt, Babylonia, China, India, Greece,
the Incas, etc. The people of these civilisations faced several practical problems
which required the development of geometry in various ways.
For example, whenever the river Nile
overflowed, it wiped out the boundaries between
the adjoining fields of different land owners. After
such flooding, these boundaries had to be
redrawn. For this purpose, the Egyptians
developed a number of geometric techniques and
rules for calculating simple areas and also for
doing simple constructions. The knowledge of
geometry was also used by them for computing
volumes of granaries, and for constructing canals
and pyramids. They also knew the correct formula
to find the volume of a truncated pyramid (see
Fig. 5.1).You know that a pyramid is a solid figure,
the base of which is a triangle, or square, or some
other polygon, and its side faces are triangles Fig. 5.1 : A Truncated Pyramid
converging to a point at the top.