Virtual Protractor
Use the slider or type a number to draw an angle. Watch how the shape and its name change as it grows!
It is smaller than a perfect corner (less than 90°).
The Family of Angles
An angle is formed when two lines meet at a single point (called a vertex). We measure how wide open these lines are using degrees (°). A full circle is 360°. Here are the main types of angles you need to know:
Acute Angle
Between 1° and 89°
Think of it as a "cute," small angle. A slice of pizza is usually an acute angle!
Right Angle
Exactly 90°
It makes a perfect square corner. The corners of your books and computer screens are right angles.
Obtuse Angle
Between 91° and 179°
A very wide, open angle. Think of a recliner chair leaning back.
Straight Angle
Exactly 180°
It lies completely flat, creating a perfectly straight line.
Reflex Angles (Advanced)
If you push a straight line even further down, you get a Reflex Angle (between 181° and 359°). It represents the "outside" of a standard angle! If you go all the way around to 360°, it is called a Full Rotation (a complete circle).