PRACTICAL GEOMETRY - ESSENTIAL POINTS

• Ruler: A ruler is used to measure the length of a line segment.
• Compass: A compass is a V-shaped instrument used to construct circles or arcs of circles.
• Protractor: A protractor is a geometric instrument in the shape of a semi-circular disk, used to measure the size of an angle in degrees.
• Divider: A divider is used to measure and compare the lengths of the line segments.
• Set-squares: Set-squares are triangular in shape and are of two types. One with 90°, 45° and 45° angles and other with 90°, 60°, 30° angles at the vertices.
A circle is the shapeconsisting of all the points that are equidistant from a fixed point.
The circles drawn with the same centre but with the different radii are called Concentric circles.
A line segment is a part of a line bounded by two end points.Line segments can be constructed in two ways:
• Construction using ruler.
• Construction using ruler and compasses.

Two lines (or line segments) are said to be perpendicular to each other if angle between them is 90°. It can be constructed in two ways:
• Using ruler and set square.
• Using ruler and compasses.

Perpendicular bisector of a line segment divides a line into two equal halves at an angle of 90°.
An angle is formed when two rays called arms of the angle meet at a common point.
Bisector of an angle divides the angle into two equal halves.