Vertical Angles

The rotors of this helicopter are an example of vertical angles. Vertical angles are formed by a pair of non-adjacent angles that are formed by the intersection of two straight lines. The rotors are two straight lines that are non-adjacent and intersect. Helicopters are used for air transportation, and are specific to the aerospace industry.

I found this picture online at http://visual.merriam-webster.com/transport-machinery/air-transport/examples-helicopters/ambulance-helicopter.php