Angles

• Middelbare school
• vwo
• Leerjaar 1

Angles

An angle is the space between two line segments
Just like we measure the length of a line segment
or we calculate the area of a 2D-shape
or the volume of a 3D-shape

Angles

First of all we need to give angles a unit, degrees
A full angle (a circle) is always 360 degrees

Angles

If we draw a straight line, and we measure the top half of the line we get a straight angle which is 180 degrees
We write:

∠A=180°

Angles

Now if we cut the straight angle in half we get a right angle
Since angle B is between points A and C
We can write

Or we write
This has exactly the same meaning

∠ABC=90°

∠B=90°

Angles

Now there are also angles that are smaller than right angles and that are larger than right angles.
Acute angles are always between 0 and 90 degrees
Obtuse angles are always between 90 and 180 degrees

Angles

In the next few slides you will be tested on your knowledge about angles.

How many degrees is a right angle?

1. 0
2. 360
3. 90
4. 180

How many degrees is a straight angle?

1. 0
2. 360
3. 90
4. 180

How many degrees is a full angle?

1. 0
2. 360
3. 90
4. 180

What kind of angle do you see on the right?

1. Straight angle
2. Obtuse angle
3. Acute angle
4. Right angle

What kind of angle do you see on the right?

1. Straight angle
2. Obtuse angle
3. Acute angle
4. Right angle

What kind of angle do you see on the right?

1. Straight angle
2. Obtuse angle
3. Acute angle
4. Right angle