#Protractor angles how to

#Protractor angles how to

How to Use a Protractor to Draw Angles?Ī protractor can be used to measure and draw angles. A common protractor is in the shape of a semicircle that has an inner and an outer scale with markings from 0° to 180° on it. To reduce errors, align the baseline and vertex properly.įAQs on Protractor What is a Protractor in Geometry?Ī protractor is a simple measuring instrument that is used to measure or draw angles in degrees.If the angle to be measured is on the left-hand side from the center of the protractor, we use the outer readings of the protractor and if the angle to be measured is on the right-hand side of the center, we use the inner readings.The angle protractor tool and 360° protractor give more precise measurements. We can also use a 360° protractor to draw a reflex angle.It is commonly used in the field of architecture, mechanical drawings, and meteorology. Therefore, ∠CAB = 40°.Ī 360° protractor is circular in shape and has readings up to 360° in the clockwise direction. Step 5: Now using a scale, join A and C.Step 4: In the inner readings, look for 40º and mark it as point C.Step 3: Since the angle is drawn on the right-hand side of the vertex we will see the inner readings.Step 2: Align the baseline of the protractor on AB such that the center of the protractor is placed on point A.Let us see how to draw an angle of 40º using a protractor.

In order to draw angles using a protractor, we use the following steps. This can be verified by the values, that is, 150º + 30º = 180º. It should be noted that ∠AOC + ∠BOC form a straight line and hence add up to 180. Step 2: Check the reading where the ray OC is formed.Since we need to measure ∠AOC, which is formed on the left-hand side of the center, we will use the outer readings which go clockwise. Step 1: Place the baseline of the protractor on line AO such that the centre of the protractor is placed on vertex O.Now, let us find the measure of ∠AOC using the following steps. Step 3: Now, identify the reading on the protractor where ray C is extending.

Step 2: Since the angle is formed on the right-hand side of the center, we will use the inner readings which go anti-clockwise.

Step 1: In order to measure the angle ∠BOC, align the baseline of the protractor with the line AB such that the center circle of the protractor is at the vertex O.

In this case, ∠BOC = 120°.įor measuring angles with a protractor, let us use the following steps and relate to the figure given below.

Step 4: If the angle to be measured is formed on the right-hand side from the center of the protractor, we need to use the inner readings of the protractor.

If the angle to be measured is formed on the left-hand side from the center of the protractor, we need to use the outer reading of the protractor.

Step 3: Decide which readings are to be followed.

Step 2: Place the baseline of the protractor on the ray which is the base of the angle.

Step 1: We first need to pIace the center (hole) of the protractor on the vertex O.

Observe the following figure to know how to read a protractor and relate to the steps given below. Each inner reading and outer reading supplements each other, i.e., they add up to 180°. How to Read a Protractor?Ī protractor can be read using its inner readings or its outer readings depending on the angle that is formed. It has two readings - the outer reading and the inner reading that help to measure a given angle.

On, the exercise tells me.A protractor is an instrument which is very easy to use. So this is an acuteĪngle right over here. Side opens up or you could say points to 70 degrees. So you want the 0ĭegrees on the side, so the other side is But this isn't too helpful,īecause the angle is now outside. Vertex of my angle at the center of my protractor. And this looks like roughlyĪn 80 degree angle, not quite. So once again, put theĬenter of the protractor at the vertex of our angle. The base of the protractor, at this side of the angle. So once again, place theĬenter of the protractor at the center, at the Ray, it points to, looks like, pretty close And the other side of theĪngle is within the protractor. Is either rotate the angle or rotate the protractor. Vertex of the angle at the center of the protractor. Protractor at the center of- or I should say, at the Want to measure an angle, what you want to do Omar Rizwan, who was actuallyĪ high school intern, made this pretty neat module. And I want to giveĬredit to the person who built this protractor, because And it's a pretty coolĪctually measure angles. Of me is the Khan Academy measuring angles exercise.