Let’s remind ourselves of some of the things we know about angles.

How many angles are there in a complete turn? If angles are on a straight line, what must they add up to?

What’s a right angle? What does it look like? How many degrees is it?

What are vertically opposite angles? What do we know about them?

Exercise

Let’s complete exercise 9A from page 130 of the textbook:

The answers are below:

Parallel lines

When a transversal crosses a pair of parallel lines, there are various properties of the angles we should know about. Let’s look at a few with the teacher.

Exercise

Let’s complete exercise 9B from pages 131 and 132 of the textbook:

The answers are below: