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Playing with

8 Constructions

8.1 INTRODUCTION Learning Outcomes

Welcome to the exciting world of geometry! In By the end of this chapter, students will be able to:
this chapter, we will explore the fascinating art of • use basic tools like the compass, protractor, and
ruler.
constructions, where mathematics meets creativity and • apply techniques to construct angles, circles,
precision. Imagine using just a ruler, a compass, and your rectangles, and squares.
skills to create perfect shapes and figures. Doesn’t that • engage in fun activities to practise their
sound fun? Constructions are not just about drawing; construction skills.
they teach us the importance of accuracy, logical thinking, and patience. You will learn how to create angles,
bisect lines, draw circles, rectangles, and much more through constructions. These skills are like building blocks
that will help you solve complex problems and understand geometry better as you progress in your studies.

8.2 KNOWING OUR GEOMETRIC TOOLS

1. Ruler: The ruler (or scale) is used to draw line segments and measure their lengths. It is a flat and
straight-edged strip where one side is graduated to
centimetres and the other to inches. It is one of the
most essential tools in geometry. Ruler or Scale
2. The compass: A compass has two legs — one leg ends in a pointer tip
and the other at a hole, where a pencil fits in. It is the most important
tool of your geometry box. The basic uses of a compass are to draw
a circle, bisect angles and lines, mark off equal lengths and measure
Legs
distances.
3. The divider: A divider is a tool which is similar in shape to a Pencil Pointer
compass. It has a pair of pointer ends. It is basically used to compare Compass Divider
lengths.
4. The protractor: The protractor is a semi-circular tool divided into
180-degree parts. The measure starts from 0° on one side and ends
at 180° on the other side. The measure goes in both clockwise (outer
scale) and anticlockwise directions (inner scale). The centre of the
semicircle is called the midpoint of the protractor. The horizontal line
is called the baseline of the protractor. The basic use of a protractor Clockwise Midpoint Anticlockwise
is to draw and measure angles. (Outer scale) Protractor (Inner scale)

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