• TheGrandNagus@lemmy.world
    link
    fedilink
    English
    arrow-up
    219
    arrow-down
    2
    ·
    edit-2
    24 days ago

    What a deviously misleading diagram.

    The triangle on the left isn’t actually a right angle triangle, as the other angles add to 100°, meaning the final one is actually 80°, not 90°.

    Therefore the triangle on the right also isn’t a right angle triangle. That corner is 100°.

    100+35=135°. 180-135=45°. So that’s 45° for the top angle.

    X = the straight line of the joined triangles (180°) - the top angle of the right triangle (45°). 180-45=135°

    X is 135°, not the 125° it initially appears to be.

    • greyfox@lemmy.world
      link
      fedilink
      English
      arrow-up
      74
      arrow-down
      5
      ·
      24 days ago

      It also doesn’t say that the line on the bottom is straight, so we have no idea if that middle vertex adds up to 180 degrees. I would say it is unsolvable.

      • TheOakTree@lemm.ee
        link
        fedilink
        arrow-up
        33
        arrow-down
        4
        ·
        24 days ago

        This is what I was thinking. The image is not to scale, so it is risky to say that the angles at the bottom center add up to 180, despite looking that way. If a presented angle does not represent the real angle, then presented straight lines might not represent real lines.

        • dream_weasel@sh.itjust.works
          link
          fedilink
          arrow-up
          5
          arrow-down
          3
          ·
          edit-2
          24 days ago

          Eh, I think @sag pretty well nailed it.

          Looks like an outer triangle with inner triangles so x = 180 - (180 - (40 + 60 + 35)) = 40 + 60 + 35 = 135

          • Habahnow@sh.itjust.works
            link
            fedilink
            arrow-up
            3
            arrow-down
            1
            ·
            23 days ago

            Can you clarify what you mean? this doesn’t make sense to me. There isn’t an “outer” triangle. There’s one triangle (the left one) that has the angles 40, 60, 80. Both triangles are misleadingly drawn as they appear to be aligned at the bottom but they’re not (left triangle’s non-displayed angle is 80, not 90 degrees). So that means we can’t figure out the angles of the right triangle since we only have information of 1 angle (the other can’t be figured out since we can’t assume its actually aligned at the bottom since the graph is now obviously not to scale).

            • dream_weasel@sh.itjust.works
              link
              fedilink
              arrow-up
              1
              ·
              edit-2
              23 days ago

              I mean to me it looks like there are two connected triangles with an implied 3rd where x is the degree measure of its apex. IFF that is true, them you can assume 180 degree totals for each triangle individually and one for the “outer triangle”.

              I totally get it if you take the perspective that none of it is to scale, but it seems unreasonable to me that a straight line is not a straight line connecting the two triangles shown. Either it’s unsolvable from that premise, or you can assume 3 triangles that compose one larger triangle and solve directly. And it seems weird to share something that is patently unsolvable.

    • GoodEye8@lemm.ee
      link
      fedilink
      English
      arrow-up
      26
      ·
      23 days ago

      I used to have teacher who deliberately made disproportionate diagrams. His reasoning was that people trust too much what their eyes see and not enough what the numbers tell them. He would’ve loved that diagram.