Angles (Elementary)

Mentor: Today we are going to learn about angles.

Student: I know what an angle is! It is two rays connected together.

Mentor: Good job! Did you read that from your book?

Student: Yes.

Mentor: Well, there are three categories of angles: acute, obtuse and right.

Let's learn what a right angle is first. Right angles are present many places in real life. Look at the corners of this room or the edges of your books. A right angle is an angle that measures 90 degrees. A right angle looks like this:

Mentor: The second type of angle is acute. An acute angle is an angle whose measure is between 0 and 90 degrees. An acute angle looks like this:

Student: Let me guess! The third type is an angle whose measure is more than 90 degrees.

Mentor: Yes, an obtuse angle is an angle whose measure is between 90 and 180 degrees. An obtuse angle looks like this:

Mentor: We also usually name angles. Look at how these lines intersect and form angles.

Student: Those lines formed 8 angles.

Mentor: Good job. Now, who can show me an acute angle?

Student: I can! It is the one on the top right.

Mentor: Right again. Who can show me an obtuse angle?

Student 2: I think it is the one on the top left.

Mentor: Correct. We need an easier way of referring to the angles we are talking about. So from now on, we will label our angles.

Mentor: Who knows the names of the angles in this picture that are acute?

Student: Do you just call them by the letter that we put there?

Mentor: Yes, that's exactly what you do. Now what are the names of the angles that are acute?

Student: Angles b, c, f, and g.

Mentor: Good job, now you know the different types of angles and how we name angles. I think you're ready to put those ideas into practice!