Skills Handbook

Using a Ruler and Protractor

Knowing how to use a ruler and protractor is crucial for success in geometry.

Example

Draw a triangle that has a 28 ° 28 degrees  angle between sides of length 5.2 cm and 3.0 cm.

• Step 1 Use a ruler to draw a segment 5.2 cm long.

  

• Step 2 Place the hole of a protractor at one endpoint of the segment. Make a small mark at the 28 ° 28 degrees  position along the protractor.

  

• Step 3 Align the ruler along the small mark and the same endpoint. Place the zero point of the ruler at the endpoint. Draw a segment 3.0 cm long.

  

• Step 4 Complete the triangle by connecting the endpoints of the first and second segments.

  

Exercises

1. Measure sides A B ¯ eh b bar  and B C ¯ b c bar  of Δ A B C cap delta eh b c  to the nearest millimeter.
2. Measure each angle of Δ A B C cap delta eh b c  to the nearest degree.
3. Draw a triangle that has a side of length 2.4 cm between a 43 ° 43 degrees  angle and a 102 ° 102 degrees  angle.

Table of Contents