What are perpendicular lines?

Perpendicular lines are two lines that meet or cross at a right angle of 90°. The small square drawn in the corner where they meet shows the right angle. The corners of squares, rectangles and most rooms are made of perpendicular lines.

Examples

• The corner of a square is made by two perpendicular sides.
• The hands of a clock are perpendicular at 3 o'clock.
• The lines in a plus sign (+) are perpendicular.

Quick facts

• Perpendicular means the lines meet at exactly 90°.
• A right angle is the angle formed by two perpendicular lines.