Perpendicular lines are lines, segments or rays that intersect to form right angles.
The symbol means is perpendicular to .
In the figure,
The right angle symbol in the figure indicates that the lines are perpendicular.
In three dimensions, you can have three lines which are mutually perpendicular.
The rays and are perpendicular to each other.
If , find .
Since , .
By the Angle Addition Postulate,
Let be the measure of .
Subtract from each side.