**What are perpendicular lines? **

In geometry, a branch of mathematics, perpendicular lines are defined as two lines that meet or intersect each other at right angles (90°).

Perpendicular lines can be found everywhere around us, like at street intersections, in rectangular window panes.

## Let's sing!

*Perpendicular lines intersect at right angles,*

*They stand tall, and never do they dangle.*

## Let's do it!

Give your children opportunities to observe perpendicular lines in objects or places around them, such as a tall tree on the ground, an electric pole on the pavement, railway intersection, corner of two adjacent walls and high buildings.