what does perpendicular mean

At a right angle, like the perpendicular height of a parallelogram is the height line straight up at a right angle from the bottom.

"Perpendicular" is a description of the relationship between two lines,

two planes, or a line and a plane.

They are perpendicular if they form right angles (90 degrees) where they cross.

- - The little lines in the 'plus' sign (+) are perpendicular.

- - the fllag-pole is perpendicular to the ground.

- - The wall is perpendicular to the floor.

- - The door is perpendicular to the floor.

- - The door is only perpendicular to the wall when it's wide open.

If it's only open a little bit, then it's still perpendicular to the floor,

but not to the wall.

- - Your legs are perpendicular to the floor when you're standing up.