1) A left angle is the opposite of a right angle.
2) On a clock, 3:00 o'clock is a right angle, but 9:00 o'clock is a left angle.
3) A left angle is when the base ray is pointing left instead of right.
Now you know why math teachers, at times, want to pull their hair out! Just to set the record straight, in case any of my students are reading this, there is no such thing as a left angle! No matter which way the base ray is pointing, any angle that contains 90○ is called a right angle.