What are angles?

Angles are useful measurements and are often measured with protractors. There are 360⁰ degrees in a circle. An angle is formed when two lines (or sometimes rays) that are straight are intersecting with each other, where the number of degrees the vertex spans can be measured. The 3 types of angles that are everywhere in our lives are obtuse, acute, and right.

Right Angles

The first type of angles is a “right angle,” which are angles that are exactly 90⁰. For example, all four angles in a square are 90⁰, so every square contains 4 right angles – a characteristic trait.

When pictures are being drawn with right angles, the artist will commonly draw another upside-down L-shape that forms a mini square with the right angle to demonstrate that they are trying to portray an angle that is exactly 90 degrees, even if it may not be exactly to scale. (It is the same the other way around, if there is not a mini square drawn around an angle, it would not be best to assume it is a right angle!)

Obtuse Angles

A second type of angle is the obtuse angle. These are angles that are wider than right angles, as they span more than 90 degrees. Consider that triangles have a total of 180 degrees in all three of their angles combined. That means that there can only be one obtuse angle per triangle, if any; if there are two, it would already sum up to 180 degrees leaving none for the third angle!

Acute Angles

Lastly, acute angles are the opposite of obtuse angles – you guessed it – they are angles that classify as being less than 90 degrees. A commonly used saying to help students remember that acute angles are the tiniest of all is that they are “a-CUTE” angles and therefore are small and cute!