Actually solved it this time

AB and ED are parallel, which we can see from vertically opposite angles, so a must be 70.

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How do you know they are parallel ? You don't know either alpha or EDB right ?

Hello again.
>parallel
Elaborate. That thing is not to scale. Even if it were, open it on paint and prolong the AB and ED.
They'll meet, and they're therefore not parallel.

Wait, something is off about this. The smaller triangle where the base is A - B, the missing angle should be 50 degrees, but the angle is obtuse.

I am trying to solve this, and I need to ask : when they say "no trigonometry", how much am I not allowed to use ?
Do I know that the sum of all angles in a triangle is 180° ?

Angle CDE is 120 and angle BDA is 40.
That would imply line CDA is 160, which means it isn't a straight line. Triangle ABC isn't even a triangle.

Mod plesase do the job

>drawing is to scale
>50 degree angle is obtuse

>remembering how to do trigonometry

We're not all at school anymore.

doesn't need to be to scale, the entire point is to solve it using angle theorems

CDE is 140.

*I mean CBD

I mean CDB. Thank god for sage

You're right.
Math is hard

>CDE is 120
Where did you get that from?
You're also missing EDB in the calculation.
It's been said countless times, but it's impossible to get a definite solution with those values alone without using trigonometry.
You can at best come up with a range of values.

Impossible. That is not a 50 degree angle. These 'objects' do not form triangles with 180 degrees therefore no other angles can be inferred.

I guess you could use non euclidean geometry but then how do you determine the plane?

The crap drawing doesn't change the fact that it's a Euclidean triangle.

the entire point of these problems is to make the question impossible to solve with a protractor
Learn some basic geometry before trying to solve things via non-euclidean methods

Have you considered that it's not to scale? BAC is clearly closer to 60 degrees, while it's supposed to be 80.

People who expect a diagram to be drawn to scale can't have done much math

People who think there might not be a solution suck at applying basic sanity checks

What did you use to draw that?

My dick.

geogebra.org/geometry

It not being to scale just fucks with my head, since I always do things visually in my head to gain a sense of space. Since this drawing is already there, I'm trying to wrap my head around it with the appropriate angles, but it's obviously not drawn to scale.

Draw a line from D to a point on BC, to be called F, such that DF is parallel to AB.

Welcome to solution town, population you.

How do you get those without using trig. It's been about 20 years since my highschool geometry.

Yes, you probably can't use trigonometric functions and the like, the sum of the angles thing is basic geometry.

>AB and ED are parallel
>which we can see from vertically opposite angles
That's not how vertically opposite angles work. All that proves is that the third angle in the A-(angle next to alpha)-B angle and the E-(angle next to alpha)-D angles are the same.

You'd know that they're not parallel as soon as you looked at the angles next to the BD and AE lines. Because one is 70/10 and the other 60/20, ED should be tilted in comparison to AB. As a matter of fact, even in this poorly drawn diagram, ED is slightly tilted in comparison to AB. It's more obvious in though.

Try again OP.

I don't like the explanations here. I will do better.

Can we determine any angle in CDE?

nevermind that

Ah. it's impossible. Now I feel a bit silly trying to do this.

It's called the Hardest Easy Geometry Problem. Completely possible using just basic geometry principles. Drawing it to scale actually helps a ton to visualize what steps you have to take to solve it

Is it actually possible? I don't see how you can find alpha without solving the triangle CED but how to find either angle CED or CDE isn't something I find how to do.

Look it up if you want, I won't spoil it for the people that want to try to solve it.

I had to look it up to solve it

It's not, a=20

For all you morans out there pining for the complete solution

...duckware.com/tech/worldshardesteasygeometryproblem.html...