• Sludgeyy@lemmy.world
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      10 months ago

      A square is a rectangle, but a rectangle isn’t necessarily a square

      Same with rhombus and diamond

      A rhombus is a diamond, but a diamond isn’t necessarily a rhombus

      Rhombus has to have four equal sides, a diamond does not.

      • hydrospanner@lemmy.world
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        10 months ago

        I think most people would say a 2D shape that they’d call a diamond would have 4 equal sides.

        I don’t think very many at all would call an elongated parallelogram a “diamond”.

        • Sludgeyy@lemmy.world
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          10 months ago

          If I took a traditional diamond shape and elongated just the bottom sides.

          I feel like most would call it a diamond still. Specific term would be a kite. Many wouldn’t come up with that, though. It’s not an elongated parallelogram. It is not a rhombus.

          “Diamonds” on bicycle playing cards have curved edges. They are not a rhombus because sides are not parallel. Most agree that it’s the classic diamond shape, though.

          • hydrospanner@lemmy.world
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            10 months ago

            If you give someone paper and a pencil and ask them, “Please draw a diamond shape.”

            Most will draw a 4 sided shape with 4 equal sides.

            • Sludgeyy@lemmy.world
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              10 months ago

              People would definitely want to elongate the top and bottom sides because they do not want to draw a sideways square, which is a rhombus, parallelogram, diamond too.

              There’s no way a human is going to draw 4 equal lines

              No one at the end is going to be like “yeah but you have to be sure all sides are equal” when they have some kind of weird kite shape.

              There’s people out there that wouldn’t count a sideways square as a diamond

              • hydrospanner@lemmy.world
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                10 months ago

                IDK why you think that “4 equal sides” is the same as “sideways square”.

                You can (and frequently do) have equal sided diamonds that aren’t “sideways squares”.

                Seems like your main issue is geometry.

                People would definitely want to elongate the top and bottom sides

                Which is fine. As long as they elongate symmetrically (which most would do), they’re still four equal sides.

                There’s no way a human is going to draw 4 equal lines

                Yes they would. In fact most would, I’d wager.

                Sounds like your concepts struggle is comprehending that “four equal sides” isn’t the same as “four equal vertices”.

                • Sludgeyy@lemmy.world
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                  10 months ago

                  There is no such thing as a diamond in geometry. The correct term is a rhombus.

                  That shape is a kite in geometry.

                  You ask 100 people what that shape is.

                  How many are going to say diamond?

                  Even the people that believe diamonds have all equal sides would say “It’s not a perfect diamond but it is diamond shaped”

                  Imagine saying “It’s not a perfect square, but it is square shaped” at a rectangle.

        • Kusimulkku@lemm.ee
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          10 months ago

          For me the shape I was thinking of was if you take a simplified 2D version of this 💎, with there being 4 sides, 2 pairs of equal sides but not 4 equal sides

          I imagine what people are talking about here is this ♦️ sort of diamond.

          I blame me not being a native speaker for thinking of diamon diamond

      • dudinax
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        10 months ago

        In practice, diamonds have equal sides.