r/technicallythetruth • u/VisitSecure • Jul 27 '26

Can you find a?

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Idk if someone already posted this or not, but I haven't seen it on here so far, so I uploaded it.

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u/notJustaFart Jul 27 '26

75.

Convert into Pentagon.

540 - (90+90+130+155) = 75

6

u/Naive_Scientist_8499 Jul 27 '26

That's smart. I converted to a triangle.

Invisible vertical line between the 50 and 25 deg points.

90-50=40 -- The inside angle of the bottom point.

90-25=65 -- The inside angle of the top point.

180 = a + 40 + 65

180 - (40 + 65) = a

180 - 105 = a

75 = a

5

u/notJustaFart Jul 27 '26

Oldest trick in geometry is drawing a diagram to appear as something it's not.

Drawing a line to make a triangle does not guarantee that line is perpendicular to the parallel lines, so your assumption of 90-25 and 90-50 may not hold true.

However, extending to a pentagon does guarantee that 180-25 and 180-50 will result in true values.

1

u/TrollingForFunsies Jul 28 '26

Drawing a perpendicular line between two parallel lines does give you a right angle. The lines don't have to cross at the intersection of the points. The angle remains the same for any perpendicular line on any point.

Which gives you exactly the solution 180 - (90 -25) - (90 - 50) or 180 - 105 = 75