My Technic math puzzle of the day

[Roland Melkert]

Trouble is, I don’t know the exact position of D relative to E’, only to AB or (local) y of B. A complication, of course, is that the shock is adjustable, so that length is not consistent.

I think you can get that because the lift arm is 9ldu from the axle hole, the shock has a radius of 10ldu, so E' is 1ldu off center.

Now using E.y and E.x+1 and the known position of C you have the lengths of CD and CE' which you can use to get the length of E'D (combine two triangles -> Pythagoras).

With a known E'D length you can get the E D length too, use this to make a new triangle out of E D and D', use that to get the length of D D' add the E.x to it and you have D.x, then you use the same triangle to get D.y

With a known D position you can make a triangle of A D B, spit it by the known 19ldu use the distance of A D and 19 to get the angle at A for this triangle.

Finally you can use AC and A A' to get the 'true' angle of A.

   

Still untested, might be fun to make an animation of this to see it all move in order to test the values.

edit: made some corrections.