Measuring angles: |
It's okay to talk about angles using
words, but it is easier to use numbers, just like we use centimetres to
measure the length of something.
In ancient history, the Babylonians believed the sun moved around the Earth. They believed it took 360 days for the sun to go around the Earth. They decided to use 360 units to turn a full circle. So today we use degrees to measure angles. A full turn has 360 degrees. |
||||||||
| Half a turn therefore has half
of 360 degrees = 180 degrees.
A quarter turn has a quarter of 360 degrees = 90 degrees. |
 |
||||||||
 |
Instead of writing out the word 'degrees' every time, we use a little circle, º, to show that we are measuring degrees. | ||||||||
Test Yourself Now!!