• bstix@feddit.dk
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          21 hours ago

          Yes sure, in Euclidean geometry, but this is clearly keyhole shaped geometry.

      • wolfpack86@lemmy.world
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        21 hours ago

        They’re also not actually right angles, as the curvature starts departing from the angles origin. They may be approximately 90, down to many many small decimal places, but they are not 90.

        • kryptonianCodeMonkey@lemmy.world
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          18 hours ago

          That’s not accurate. If you are measuring the angle of a line intersecting with a curved surface, you measure against the tangent at the point of contact/intersection. It can be and still is exactly 90 degrees.

    • Prunebutt@slrpnk.net
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      23 hours ago

      Take shitposts seriously and point out their obvious errors

      -Carl Friedrich Gauss, probably

  • Lem Jukes@lemm.ee
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    19 hours ago

    I remember enough from geometry to know this is horseshit and be annoyed at it but not enough to actually prove why

    • Codex@lemmy.world
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      22 hours ago

      The semi-circle is one side, then the 2 straight edges, and the arc between them is the 4th side.

    • UrLogicFails@beehaw.org
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      22 hours ago

      Someone may want to double-check my math on this one, but the length of the sides will be dependant on the radius of the smaller circle

      ϴ=π+1-√(π^2+1), l=(2π-ϴ)r_1, l is the length of the sides. r_1 is the radius of the smaller circle

      • m0darn@lemmy.ca
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        15 hours ago

        I look at your diagram and see:

        ϴ= L/(L+R)
        

        And

        2π-ϴ = L/R
        

        I solved those (using substitution, then the quadratic formula) and got

        L= π-1 ± √(1+π²) ~= 5.44 or -1.16
        

        Whether or not a negative length is meaningful in this context is an exercise left to the reader

        Giving (for L=5.44):

        ϴ~= 0.845 ~~48.4° 
        

        I’m surprised that it solved to a single number, maybe I made a mistake.

        • UrLogicFails@beehaw.org
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          13 hours ago

          That lines up pretty similarly with what I found also. The angle should be a constant since there is only one angle where the relationship would be true. I just left it in terms of π because I try to avoid rounding.

          Having said that, L would be a ratio of r; which I think lines up with what you found as well.