Three or More Coplanar Parallel Lines

This is a picture of a keyboard which contains more than 3 coplanar parallel lines (five are highlighted in magenta). These lines between the keys all lie on the same plane, they all have the same slope, but since they are a certain distance apart they will never intersect. The lines could be extended as far as needed and they still would not intersect. This picture is one I took of my MacBook keyboard in my house. Keyboards are used to type with computers, both laptop and desktop, along with tablets. Keyboards play a big role in professions such as graphic designer, cyber security technician, and writer. 

Non-Congruent Alternate Interior Angles

This is an image of bridge trusses that contain non-congruent alternate interior angles. The angles are drawn in red, the transversal line is in green, and the two lines are in yellow and magenta. The two  trusses are cut by another, this forms two angles inside the magenta and yellow lines and on opposite sides of the transversal that are not congruent with one another. Bridge trusses are used as support beams on bridges. They are used by thousands of commuters as they cross bridges. 

I found this image online at this website http://cte.unt.edu/content/files/_STEM/STEM_curr/EngMath/05CapstoneFinalChallenge/05FinalDesignChallenge.pptx

Vertical Angles

This is a pivot leg attached to a tray table. It contains two pairs of vertical angles (one has been outlined in red, and the other in green). It forms these angles since the angle at which the table opens is the same as the angle at which the legs open because vertical angles are congruent. Pivot legs can be found on objects of expandable furniture such a tables and chairs. It makes these tables and chairs easier to fold and store. I found this pivot leg on a tray table in my house's basement. Directors and actors have been known to stereotypically sit in chairs with pivot legs. These legs are frequently used for big events such as weddings or parties as they can be easily set up then taken down.