TABLE OF CONTENTS

There are three acute angles:

There are three obtuse angles:

There are two right angles:

Two congruent angles

are vertical angles, so they are congruent.

Two straight angles

are straight.

Complementary angles

There is only one set of angles that combine to make 90°:

Supplementary angles

There are many sets of supplementary angles. Here are three of them:

Make it rain.