Referent Angles
Completion requirements
Lesson 1: Angles - Referent Angles
Constructing Knowledge
An exact measurement is not needed for all situations. Referents can be used to get an idea of the measure of an angle without using a measuring device. An example of this is when extreme athletes in sports, like half pipe skateboarding or snowboarding, are performing tricks. When a snowboarder does a 720 or a 1080, we know he has spun 2 or 3 complete circles in the air. However, these rotations have not been officially measured. Sometimes the athletes may under rotate or over rotate a trick by a few degrees, but those errors may be imperceptible to most people.
Referent
Is an estimated measurement made by using non traditional measuring devices combined with simple logic. A referent 'refers' to an actual measurement without using an actual measuring device. |
Referents for angles are usually based on one of 3 common angles that are simple to visualize.
| Angle | diagram | description |
| 360° | 
|
full circle |
| 180° | 
|
straight line |
| 90° | 
|
right angle |
The other angles that can be estimated fairly easily using parts of the 90° angle.
| Angle measure | angle | how angle is estimated | description |
| 45° | 
|
|
half of a 90° angle |
| 22.5° | 
|
|
half a 45° angle |
| 30° | 
|
|
one-third of a 90° angle |
| 60° | 
|
|
two-thirds of a 90° angle |
By using a combination of these referent angles you can estimate angles and sketch approximate angles.
The hours on a standard clock can be used for referent angles as well. The clock is a full circle (360°) and has 12 hours, which means each hour is 30° from the adjacent hours.
2014 © Alberta Distance Learning Centre
Points to Ponder
The hours on a standard clock can be used for referent angles as well. The clock is a full circle (360°) and has 12 hours, which means each hour is 30° from the adjacent hours.
2014 © Alberta Distance Learning Centre
