Web-based Student Activities

Alphabet Geometry

Obtuse Angles

Students should be able to:

  • identify and classify obtuse angles.

Introduction to Obtuse Angles: The Letter X

You can learn a lot about angles by looking at letters. Look closely at the angles in the letter K--can you identify each of them (there are three)? One of the angles opens wider than the other two. Can you identify it?


Push the button in the mini-movie below to reveal it.
rays and vertex

Get Adobe Flash player

Use this mini-movie on your SMARTBoard

What can you learn by looking at the letter K?

Let's start by reviewing three kinds of angles:



3 angles

When the letter K is turned on its side, we see angle that looks most like angle 3, an obtuse angle. An obtuse angle is one with a measure greater than 90 degrees.


Are There Other Letters with Obtuse Angles?

There are many more letters with obtuse angles. The letter Y is one of them, but like the letter K, you have to rotate it to see them. See if you can find the obtuse angles and then click the button to reveal them.

w acute angles

Get Adobe Flash player

Push the button to see the obtuse angles.

Use this mini-movie on your SMARTBoard
Use this mini-movie on your SMARTBoard




Subscribe our newsletter
Stay up to date on all of our new, free mini-movies and student activities as they are added to the site each month.

Enter your Email



Preview | Powered by FeedBlitz