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SAI International School

CLASS – VI

Mathematics

Chapter-14: Practical Geometry-1
Lesson Notes - 1

SUBTOPICS:

1) GEOMETRICAL TOOLS

SL. GEOMETRICAL TOOLS DESCRIPTIONS USES
NO.
1 The Ruler The ruler in your instruments To draw line
[or the straight edge] box is graduated into segments and to
centimetres along one edge. measure their
lengths.

2 The Compasses A pair – a pointer on one end To mark off equal
and a pencil on the other. lengths but not to
measure them.
To draw arcs and
circles.

3 The Divider A pair of pointers To compare
lengths.

4 Set-Squares Two triangular pieces – To draw
one of them has 45°, 45°, 90° perpendicular
angles at the vertices and and parallel lines.
the other has 30°, 60°, 90°
angles at the vertices.

5 The Protractor A semi-circular device To draw and
graduated into 180 degree- measure angles.
parts.
The measure starts from 0° on
the right hand side and ends
with 180° on the left hand side
and vice-versa.