Introduction to 3D Geometry
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It's one thing when all those shapes are sitting flat on the page. But when they start popping out and invading our personal space bubble, we get a little nervous. Back off, cylinder.
|Geometry||Visualize relationships between two-dimensional and three-dimensional objects|
|Properties, Measurement, and Dimension||Visualize relationships between two-dimensional and three-dimensional objects|
Only, they're not triangles anymore... They're prisms! Horrible, gory, flesh-eating
prisms. Ever seen light refracted through those glass
shapes to make a rainbow?
3D shapes have more than just length and width.
They have depth, too. Most 3D shapes you can make by gluing a bunch
of 2D shapes together. Be careful with the krazy-glue, though...
...you don't wanna walk around with a cylinder glued to your head.
A flat surface of a shape is called a face... ...the line that connects two faces is called
an edge... ...and a point on a 3D shape is called a vertex.
Prisms are two parallel polygons called bases with a bunch of lateral faces that connect
them. They're named after the shape of their bases,
so we could have... ...triangular prisms or...
...hexagonal prisms. Cylinders are like prisms, only the bases
are circles instead. Pyramids are like prisms, but with only one
base. And cones are pyramids with circular bases.
Spheres are like balls... but don't try playing basketball with one.
They're not regulation. Those are the basic three-dimensional shapes,
and the ones you'll probably see often. There are other ones like polyhedrons, but
we won't blow your mind any more for the time being.
Now that you've got a grip on basic 3D geometry... ...you can sit back, relax, and enjoy Revenge
of the Triangles... in 3D...
...or... try to.