Using a protractor
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This document provides instructions for using a protractor to measure and draw angles. It explains that a protractor should be lined up with its vertex (upside down T) at the vertex of the angle being measured. The reader is shown how to find the degree measurement by looking at the numbers on the protractor, being careful to also consider the 1 degree markings for angles greater than 30 degrees. The learning objectives are to use a protractor to measure and draw acute and obtuse angles to the nearest degree and to calculate angles on a straight line.
Using a protractor
- 1. 421 0011 0010 1010 1101 0001 0100 1011 Measuring, calculating and drawing angles... Our learning objectives today To use a protractor to: a) measure acute and obtuse angles to the nearest degree. b) draw acute and obtuse angles to the nearest degree. To calculate angles on a straight line.
- 2. 421 0011 0010 1010 1101 0001 0100 1011 What do we use to help us? A protractor Here is a standard protractor like you use in the classroom.
- 3. 421 0011 0010 1010 1101 0001 0100 1011 When we use a protractor, we need to line it up correctly. You need to make sure the protractor is lined up correctly. Is this ready to measure the angle?
- 4. 421 0011 0010 1010 1101 0001 0100 1011 Were you right......................it wasn’t Look for the upside down ‘T’ in the middle of the straight line on your protractor. This needs to be exactly on the vertex of your angle.
- 5. 421 0011 0010 1010 1101 0001 0100 1011 We need to remember..... It doesn’t matter which way round the angle is, you ALWAYS need to line the upside down ‘T’ to the vertex of the angle.
- 6. 421 0011 0010 1010 1101 0001 0100 1011 Now you are ready. Read from the 0°, and follow the inner set of numbers.
- 7. 421 0011 0010 1010 1101 0001 0100 1011 Once you reach 30° you need to be careful!!! You then need to look at the 1° markings on the outer set of numbers.
- 8. 421 0011 0010 1010 1101 0001 0100 1011 What does it measure? This angle measures 35°.
- 9. 421 0011 0010 1010 1101 0001 0100 1011 Measuring, calculating and drawing angles... Remember our learning objectives today are To use a protractor to: a) measure acute and obtuse angles to the nearest degree. b) draw acute and obtuse angles to the nearest degree. To calculate angles on a straight line.
- 10. 421 0011 0010 1010 1101 0001 0100 1011 Measuring, calculating and drawing angles... Remember our learning objectives today are To use a protractor to: a) measure acute and obtuse angles to the nearest degree. b) draw acute and obtuse angles to the nearest degree. To calculate angles on a straight line.