TenMarks teaches you how to identify prisms and cones.
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Learn about Prism and Cones In this lesson, we will learn about prisms and cones—are the three dimensional figures. We need to name each of the three dimensional figures given to us and we also have to tell whether they are polyhedrons. Again, polyhedrons have flat surfaces. All surfaces are flat and they’re also polygons. So let’s look at part A What do we see? We see one vertex, we see a rectangular base. Actually it’s a square base. Squares are rectangles too and we see one, two, three and four triangular faces and we see one vertex on top. There are actually four more vertexes but it’s got a vertex on top. Such a figure is called a Pyramid. If you have a polygon as a base and the rest of the faces are triangles and there’s a single vertex on top, it’s called the Pyramid. In order to name the pyramid, we look at the shape of the base. It’s a square base so this is a square pyramid. Let’s look at the second one. Well, this is a polyhedron. We see there’s a curve surface. The moment that we see a curve surface, we know this is not a polyhedron. But what if we name this figure? We see a vertex and we see a circle as a base so it’s got a circular base and a vertex on top. Such a figure is called a cone. Remember that. The last one—we see something shaped like a ball. It has no flat surfaces so of course it is not a polyhedron. It’s not a polyhedron. And because it’s basically no flat surfaces, it’s all curved surfaces, this is called a sphere.