Video: Determining Whether a Shape Is 2D or 3D

Which of these shapes is 3D?

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Video Transcript

Which of these shapes is 3D?

In this question, we’re shown pictures of two shapes. And they look very similar at first glance. But if we look more carefully, we can see that they’re actually different shapes. Our first shape is a pyramid. It has a flat base and several surfaces that go up to a point. It’s just like the pyramids that were built in ancient Egypt. And our second shape, we know, is a triangle. Our question asks us, which out of our two shapes, the pyramid or the triangle, is 3D? 3D is a short way of saying the words “three dimensional.” A shape with three dimensions has got length, width, but it’s also got height. A 3D shape is a solid shape, not a flat shape. It’s more of an object.

So out of our pyramid and triangle, which one is a solid shape, not a flat shape? We can see that the pyramid is a solid shape. A triangle is a flat shape. When we think of those huge pyramids in ancient Egypt, these are big objects. They’re not flat on the ground, they’re very, very tall. A pyramid is a 3D shape.