Have You Got The Angle? Created by Dave Plummer Vogel Intermediate School CISD for the Texas Center for Academic Excellence Tek 6.6A Obj.3 Hi boys and Girls! Today, we are going to learn about Angles. Angles are everywhere! And they have different types. At the end of this lesson, you will know about three different types of angles. During this activity, click the continue with your left mouse button to go on to the next slide.

What is An Angle? When two lines meet or cross, they form an Angle. When two lines meet, they form an angle. These can be lines that are drawn on a piece of paper, they can be objects that form a line. Try this– Hold one arm straight above your head. While keeping that arm in place, stretch your arm straight out toward the wall. You have just made an angle and your head is right in the middle of it. In the picture, you can see an angle drawn. The girl on the right is forming an angle with her arms. How many angles can you see around the room?

Check out These Angles Here is a picture of the first day of school in our brand new school. Notice how all the lines that meet form angles? I put two of them in red. There are many many more. Look around the room where you are. How many angles can you find?

The Three Types of Angles The Right Angle The Acute Angle The Obtuse Angle Angles have different types. Look at the first angle. It’s lines are half of a rectangle or a square. In fact, you could put two of those together and make a square. It is called a “right Angle”. The second angle is smaller, isn’t it. Don’t you think it’s kind of cute? We call it an “acute angle”. Any angle that is smaller than a right angle is an acute angle. The third angle, it’s real wide. It’s wider than a right angle, isn’t it. We call it an Obtuse angle. Now, before you click to go on, study these angles very carefully. I’m going to ask you what each of them is. See if you can get a perfect score.

What is this Angle? Click on the correct answer below 1. A Right Angle Look at the angle in this picture. Is it a Right Angle? If so, click the number 1 choice. I is An Acute Angle? If so, click the number 2 choice. Or is it an Obtuse angle. If so, click the number 3 choice. Click on the correct answer below 1. A Right Angle 2. An Acute Angle 3. An Obtuse Angle

You’re Right!!! Great Job!! An acute angle is smaller than a right angle. Click the

Let me help you? A right angle Now remember, an acute angle is one that is smaller than a right angle Look at the right angle. Isn’t the other angle smaller? Click the “next button” to try this one again! A right angle

What is this Angle? 2. An Acute Angle Look at the angle in this picture. Is it a Right Angle? If so, click the number 1 choice. I is An Acute Angle? If so, click the number 2 choice. Or is it an Obtuse angle. If so, click the number 3 choice. Click on the correct answer below 1. A Right Angle 2. An Acute Angle 3. An Obtuse Angle

You’re Right!!! Great Job!! You’re right and the angle is right also! Click the Next button to continue

Look at this one again I’m going to help you a bit on this one and give you another try. Look at the angle. Remember how the right angle looks like part of a square or rectangle? This one does too, doesn’t it. Now click to try again!

What is this Angle? Click on the correct answer below 1. A Right Angle Look at the angle in this picture. Is it a Right Angle? If so, click the number 1 choice. I is An Acute Angle? If so, click the number 2 choice. Or is it an Obtuse angle. If so, click the number 3 choice. Click on the correct answer below 1. A Right Angle 2. An Acute Angle 3. An Obtuse Angle

You’re Right!!! Great Job!! An obtuse angle is larger than a right angle.

Let me help you? A right angle Now remember, an obtuse angle is one that is larger than a right angle Look at the right angle. Isn’t the other angle larger? Click to try this one again! A right angle

Let’s Measure Some Angles Now that you know the Right angles, acute angles, and obtuse angles, we are going to learn to measure them. Angles are measured in degrees. But these degrees have nothing to do with the temperature. To measure an angle in degrees, we use a tool called a protractor. Here is a picture of a protractor. To measure angles, we use a Protractor

A Right Angle is 90° Protractors are usually made of clear plastic so that you can see right through them. You just lay the protractor on top of the angle that you wish to measure. Here’s our old friend, the right angle. The bottom line is directly over the zero. We get our reading from the tall line. It is right over the 90 degree line, isn’t it. So remember this- A right angle is 90 degrees.

An Acute Angle is less than 90° Here’s an acute angle. Do you see how we line up the tip of the angle with the center of the protractor? The bottom line is still directly over the zero. How many degrees is this angle? An acute angle is less than 90 degrees.

Here are more acute angles- both less than 90 degrees. Here are two more acute angles. One is much smaller than the other, but as long as they are less than 90 degrees which is the size of the right angle, they are acute.

An Obtuse Angle is more than 90° Here’s an obtuse angle. It is more than 90 degrees. It’s a bigger angle than the right angle.

Here are more obtuse angles- both more than 90 degrees. Here are two more acute angles. One is much smaller than the other, but as long as they are less than 90 degrees which is the size of the right angle, they are acute.

Angles Can Face Different Directions This is a right Angle Here’s another When two lines cross evenly four right angles are the result. How about a game of Four Square? And another And one more

What are each of these? Acute, or Obtuse angles? When these two lines cross, four angles are made here, too. Look at them carefully. I have named the angles A, B, C, and D by putting the letters inside the angles. Two of them are small and two of them are larger. Which two are Acute Angles? Which two are Obtuse angles? C D

What are these? B A C D Obtuse Acute Acute Obtuse If you chose A and C as the Acute angles, you are right! And B and D are the large ones, or the Obtuse Angles. Pat yourself on the back. C Acute Obtuse D

You’ve Got the Angle!!! Texas Center for Academic Excellence © 2001 Contact the Texas Center for Academic Excellence at txcae@shsu.edu or visit our website at http://www.shsu.edu/~txcae Linda Creighton - Director Well, you’ve done a great job. Now when you look at shapes from now on, you will be better able to describe them to others!