Back to module 2 notes

Measuring Angles

You need a protractor:

Step 1: Place your protractor over the angle with the center

of the protractor on a vertex and the zero lined up with the ray

of the angle.

 

Step 2: Find the zero on the protractor and follow the scale

until you hit the next ray.  Read the number.  That is the measure of the angle.

As you can see, this angle measures 134.  Check the angle to make sure it is obtuse.

 

Drawing Angles

Let's say you want to draw angle CDE with a measure of  78.

Step 1: Draw one side of the angle, ray DE.

 

 

 

Step 2: Place the center of the protractor on the vertex, point D.

 Line up the ray with the base line of the protractor, at 0.

 

 

 

 

Step 3: Follow the numbers as they increase from 0.

 Mark a point at 78.

 

 

 

 

 

Step 4: Draw a second ray from the vertex through the point: