GeoGebra Classroom

# Copy a Segment

Drawings of geometric figures are created using measuring tools such as a ruler and protractor. Constructions are methods of creating these figures without the benefit of measuring tools. Generally, only a pencil, straightedge, and compass are used in constructions. Sketches are created without the use of any of these tools.

## Construction Steps

A compass can be used to create two equal segments, a copy, instead of using a ruler to measure. Step 1: Use the "segment between two points" button image to draw points A and B connected by a segment. To create, select the button and then two locations anywhere in the window. Step 2: Use the "new point" tool to draw point C anywhere in the window. Step 3: Select the "compass" (circle) button. Choose points A and B to define the size of the circle which also represents the length of the line. Then, choose (select) point C to direct the program to create a circle with center point C, also known as Circle C, or ⊙C. Step 4: Create a fourth point anywhere on the edge of ⊙C with the "new point" tool. Step 5: Use the "segment between two points" button to construct a segment between point C and your new point. Step 6: Use the "distance or length" tool to measure the length of your original and new segment. The measurements should be equal. Step 7: Create a fifth point anywhere on the edge of ⊙C with the "new point" tool. Construct a segment between point C and your new point. Step 8: Again use the "distance or length" tool to measure the length of your new segment. This measurement should also be the same. Step 9: Use the "ABC" tool to first write your name and then answer the questions: What would happen if you chose a 6th point on ⊙C and measured the segment? Why would this pattern continue? What is the relationship between the circle and each of the segments? Step 10: Take a screen shot of your work below.