Lesson 1: Angles - Replicating Angles with a Protractor and Ruler

   Constructing Knowledge

At times, you may be required to replicate an angle. A replica is an exact copy. To replicate an object means to make another object that is the same as the first. For example, making trusses for a roof requires angles that are the exact replicas of an original angle.

Two methods for replicating angles will be introducted in this course. The first method uses a protractor and a ruler, using the following steps.

Step 1: Measure the given angle with a protractor.

Step 2: Draw a horizontal line with a ruler. Mark the vertex.

Step 3: Lay the protractor on the line so that the origin lines up with the vertex mark. Measure the number of degrees for the angle replica, and mark the angle point.

Step 4: Connect the vertex to the angle point with a ruler.

Step 5: Check the replicated angle by measuring with a protractor.

EXAMPLE

Replicate the following angle using a protractor and a ruler.



Solution


Step 1: Measure the given angle with a protractor.



The original angle is 43°.

Step 2: Draw a horizontal line with a ruler. Mark the vertex.



Step 3: Lay the protractor on the line so that the origin lines up with the vertex mark. Measure the number of degrees for the angle replica, and mark the angle point.



Step 4: Connect the vertex to the angle point with a ruler.



Step 5: Check the replicated angle by measuring with a protractor.



The replicated angle measures 43°, which matches the original angle.


Now, it is your turn! Complete the questions in your Chapter 6, Lesson 1 Practice Makes Perfect that refer to Replicating Angles with a Protractor and Ruler.



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