Well…to understand geometry you must first understand angles and parallel lines.

When lines look like this:

They are parallel. The symbols of arrows show that the lines will never touch

These are supplementary angles:

Supplementary angles add up to 180…seeing how a line alone measures 180 degrees by itself

This is obviously a right angle


When a transversal cuts through a line

That makes two angles that are equal to each other, they are called vertical angles
vertical angles are directly across the point from one another
These are vertical angles


When a transversal cuts through parallel lines, we have many angle relationships
There are:
-Corresponding angles
-Alternate interior angles
-Same side interior angles
-Alternate exterior angles
-Same side exterior angles
-Supplementary angles
-Vertical angles

I’m pretty sure that might be confusing to try to work through in your head, but that’s why I have Photoshop…to draw you examples!








when you move these angle relationships around they will either equal each other or add up to 180 degrees
These equal each other:
- Corresponding angles
- alt-int angles
- alt-ext angles
- vertical angles
These all equal each other because, to put it simplest, you can slide angles down and up the transversal, and in some cases slide them around to make vertical angles
Vertical angles equal each other because they are a reflection of each other

These add up to 180:
- Same side Interior
- Same side exterior
- Supplementary

These angles add up to 180 because of the same reason, if you slide them up or down the transversal, they will become supplementary

angles and parallel lines are used a lot in geometry, and obviously you don’t have to do this, but if you want to…try this example;



if you do choose to do the example you may PM me the answers, also if you have questions PM me, or email me, or tell me to get in the chat box

Pm-ing the answers!