What is a right angle?
When an angle between two lines is exactly 90° it is called a right angle. Two lines are perpendicular to each other.
1. Study the marked angles on the objects below.
Each of the marked angles is a right angle.
2. Which of the angles below is smaller than a right angle?
Which one is greater than a right angle?
Which one is a right angle?
Let's use a ruler to check for right angles.
3. How many right angles are there in each figure below?
Figure A has 1 right angle.
Figure B has 4 right angles.
Figure C has 2 right angles.