


Everyday Examples 


Perpendicular Lines:
Two lines are perpendicular if they intersect at a right angle. 
Perpendicular lines are very important not
only in geometry, but in science and engineering. Graphs in either
two or three dimensions have axes at right angles to each other. Gravity acts
perpendicularly to the horizontal. The tangent of a circle is perpendicular to
its radius. In buildings, walls must be perpendicular to floors. How many other
perpendicular relationships can you find?


