Step by step
The question
Question: find what kind of angle 90° is.
1 Compare with 90° and 180°
There are five kinds of angles.
Each name says how big the angle is, next to 90° and 180°.
90 is exactly 90.
90 = 90
Careful!
Look at the size next to 90° and 180°.
Careful: right: exactly a square corner
2 Name it
So 90° is right.
90° is right
3 Check
Let's check with the picture.
The dashed line up makes a square corner: 90°.
The dashed line to the left makes a straight line: 180°.
Our angle fits the square corner exactly.
So it is a right angle.
Let's look back.
First: compare with 90° and 180°.
Then: name it.
Last: check.
Answer
90° is right