How do you draw angles greater than 180?

Answer 1

First, if the angle is 360° or more, find the remainder of the angle divided by 360 - this is as 360° represents a full turn.

If you have a 360° protractor just measure off the angle.

If you only have a 180° protractor, then there are two ways it can be done as the protractor is marked so that 0° - 180° can be measured from either end of the base line:

Method 1: excess over 180°

1) Subtract 180° from the angle to get the excess over 180°.

2) Place the protractor on the line, centred on the vertex of the angle on the left of the line, with the top 0°/180° mark on the line.

3) Measure the excess over 180° calculated in step 1 from the bottom 0° mark of the protractor.

4) Draw in the second angle arm - the reflex angle (measured clockwise) is as required.

Method 2: acute/obtuse angle of the reflex angle to complete a full turn

1) Subtract the angle from 360° to get the angle which completes the full turn

2)Place the protractor on the line, centred on the angle vertex on the left of the line, with the top 0°/180° mark on the line.

3) Measure the angle to complete the full turn calculated in step 1 from the top 0° mark of the protractor (on the line).

4) Draw in the second angle arm - the reflex angle (measured clockwise) is as required.

The above assume a clockwise angle is being drawn from a vertical line with the angle vertex at the bottom.

For anticlockwise angles, place the protractor on the right of the line.

For a non-vertical line [mentally] rotate the paper so that the first arm of the angle is vertical with the angle vertex at the bottom.