Protractor is an important instrument in geometry. Before we talk about the construction of an angle using a protractor, let us recall the angles and the types of angles. An angle is made up of two rays that start from a common point. That common point is known as the vertex of the angle and the two rays that form the angle are called its arms.
Depending upon the inclination between the two arms an angle may be acute (less than 90 degrees), obtuse (greater than 90 degrees), right angle (equal to 90 degrees). The construction of angles plays an important role in geometry. In this article, we will discuss the Construction of an Angle Using a Protractor with examples.
Do Refer:
What is Protractor?
A protractor is a semi-circular disc used to draw and measure the angles. There are two ways to measure the angles. One set is from 0 to 180 degrees and the other set is from 180 to 0 degrees.
How to Draw an Angle Using a Protractor?
In order to construct or measure the angles may be acute, obtuse, or right angle we need a protractor. Let us see some steps on the construction of angles using a protractor from here.
1. Draw a line segment, which is one of the arms that is to be constructed.
2. Place a protractor with its point on the point of the given line segment.
3. The protractor has two-way markings. We consider the scale which has 0 degrees near the point for construction.
4. Join the points.
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Construction of Angles Using a Protractor Examples
Example 1.
How to Construct 90 degrees using a protractor.
Solution:
Draw a line segment BC, which is one of the arms of the angle that is to be constructed.
Place the protractor with its point O on the point B of the line segment BC.
Align OQ along the edge BC.
The protractor has two-way markings. We consider the scale which has 0 degrees near point C for construction. Mark point A next to the 90 degrees mark on the scale.
Join points A and B. ∠ABC = 90 degrees is the required angle.
Example 2.
How to Construct 75 degrees using a protractor.
Solution:
Draw a line segment BC, which is one of the arms of the angle that is to be constructed.
Place the protractor with its point O on the point B of the line segment BC.
Align OQ along the edge BC.
The protractor has two-way markings. We consider the scale which has 0 degrees near point C for construction. Mark point A next to the 75 degrees mark on the scale.
Join points A and B. ∠ABC = 75 degrees is the required angle.
Example 3.
How to Construct 110 degrees using a protractor.
Solution:
Draw a line segment BC, which is one of the arms of the angle that is to be constructed.
Place the protractor with its point O on the point B of the line segment BC.
Align OQ along the edge BC.
The protractor has two-way markings. We consider the scale which has 0 degrees near point C for construction. Mark point A next to the 110 degrees mark on the scale.
Join points A and B. ∠ABC = 110 degrees is the required angle.
Example 4.
How to Construct 80 degrees using a protractor.
Solution:
Draw a line segment BC, which is one of the arms of the angle that is to be constructed.
Place the protractor with its point O on the point B of the line segment BC.
Align OQ along the edge BC.
The protractor has two-way markings. We consider the scale which has 0 degrees near point C for construction. Mark point A next to the 80 degrees mark on the scale.
Join points A and B. ∠ABC = 80 degrees is the required angle.
Example 5.
How to Construct 160 degrees using a protractor.
Solution:
Draw a line segment BC, which is one of the arms of the angle that is to be constructed.
Place the protractor with its point O on the point B of the line segment BC.
Align OQ along the edge BC.
The protractor has two-way markings. We consider the scale which has 0 degrees near point C for construction. Mark point A next to the 160 degrees mark on the scale.
Join points A and B. ∠ABC = 160 degrees is the required angle.