Trigonometry
Angles
What’s the deal with angles anyway?
Before we even get into trigonometry, we need to discuss angles. Don’t worry. Things are not going to get too crazy. I promise.
Let’s go over the basics first.
Degree. One-three-hundred-and-sixtieth of the circumference of a circle. It is also the unit by which we measure angles.
![](https://pressbooks.bccampus.ca/trigforelectricians/wp-content/uploads/sites/496/2018/07/cirlce-226x300.png)
Angle. This is the space between two intersecting lines.
![](https://pressbooks.bccampus.ca/trigforelectricians/wp-content/uploads/sites/496/2018/07/angle-300x215.png)
Complementary angles. These are two angles whose sum equals 90 degrees.
![](https://pressbooks.bccampus.ca/trigforelectricians/wp-content/uploads/sites/496/2018/07/complimentary-angles-238x300.png)
Supplementary angles. These are two angles whose sum equals 180 degrees.
![](https://pressbooks.bccampus.ca/trigforelectricians/wp-content/uploads/sites/496/2018/07/Supplementary-angles-300x161.png)
Acute angle. An angle that is less than 90 degrees.
![](https://pressbooks.bccampus.ca/trigforelectricians/wp-content/uploads/sites/496/2018/07/Acute-angles-295x300.png)
Obtuse angle. An angle that is greater than 90 degrees.
![](https://pressbooks.bccampus.ca/trigforelectricians/wp-content/uploads/sites/496/2018/07/obtuse-300x193.png)
Similar angles. It is possible for triangles to each have different sized sides but share the same sized angles. These are called similar angles.
![](https://pressbooks.bccampus.ca/trigforelectricians/wp-content/uploads/sites/496/2018/07/Simalar-triangles-227x300.png)
Right angle. This is an angle that is 90 degrees.
![](https://pressbooks.bccampus.ca/trigforelectricians/wp-content/uploads/sites/496/2018/07/right-angle-238x300.png)
There is a ton of information about angles that we don’t need to get into. Remember: Try not to overcomplicate things. Just focus on the basics and you’ll be fine.
Next up: Triangles