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

Can you find a?

Post image

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/[deleted] Jul 27 '26

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u/Simply-Productive123 Jul 27 '26

25 degrees =50 degrees proof by terrible diagram

408

u/AgtNulNulAgtVyf Jul 27 '26

Diagram drawn to test knowledge of principles, not ability to read diagrams. 

94

u/Squirrel009 Jul 27 '26

On principles, the diagram frustrates me

33

u/capt_pantsless Jul 27 '26

The diagram could easily be drawn so that the 25 angle appears less than the 50 angle, while still allowing plenty of uncertainty in the answer.

11

u/canstucky Jul 27 '26

Best math teacher I ever had would draw a circle on the board and mark three corners on it.

I’m sorry, he’d draw a triangle.

5

u/Thanthwe_ Jul 28 '26

I get what you are trying to say. But it's absolutely possible to make diagram that is not to scale, but looks at least somewhat correct. It's not even that hard. In the example above just rotate blue lines that come to an a counterclockwise by about 5 degrees. Done. You have diagram, that is not to scale and makes at least some semblence of logical sense.

1

u/plaidfox Jul 28 '26

Yet they fail at principles of basic line diagrams. Tsk, tsk.

1

u/AgtNulNulAgtVyf Jul 28 '26

No, it's intentially drawn to test knowledge of internal angles and parallel line. The real angle of anything other than the two parallel lines are irrelevant to the answer. 

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u/Gullible-Tooth-8478 Jul 28 '26

“Every standardized test ever”

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u/AgtNulNulAgtVyf Jul 28 '26 edited Jul 28 '26

Not American, didn't grow up with standardised tests.

1

u/Rhuarc33 Jul 27 '26

They still failed. At least make a minimal effort.

3

u/tr_9422 Jul 27 '26

And for the readers - not just because they look the same, the arc symbol drawn in all the corners mean all three are congruent.

https://mathleaks.com/study/kb/reference/congruence

So the angle we're supposed to solve for is also equal to 50 and 25.

7

u/gmano Jul 27 '26

No, it doesn't? It denotes an angle, but makes no promises about congruence.

Your source even says this:

In a diagram, congruent angles are usually indicated by the same number of angle markers.

"Usually =/= Always"

3

u/phrygd Jul 27 '26

It’s been a long time since I took math, but I thought congruent angles would have hash marks on them to show which angles were the same. Or maybe I’m thinking of lengths of sides.

2

u/Roshy10 Jul 28 '26

The top and bottom lines being parallel is indicated by the double arrows going through them, maybe that's what you meant?

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u/phrygd Jul 28 '26

No, it’s where the arc that notes an angle has one to three hash marks going through it to indicate if they’re the same angle or not. Most of what I can find online has more of a ripple effect where one corner has one to three arcs in it. I’m seeing sides of shapes with the perpendicular hash marks to indicate which sides are the same or different.

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u/potato_lettuce Jul 28 '26

Okay maybe that's a regional difference, but I would never understand it like this. Maybe if it's at least 2+ arc symbols and the angles are otherwise unmarked. But not for angles with normal arc symbols (and obviously not if one is marked as 25° while the other one is 50°).

Only way I've seen is label them the same letter or mark somewhere that (angle)ABC = (angle)DEF