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Math III Videos 103 videos

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Introduction to 3D Geometry 55503 Views


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Description:

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.

Language:
English Language
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Transcript

00:00

3D Geometry, a la Shmoop. Take a seat. Revenge of the Triangles... in

00:09

3D... is about to begin.

00:11

Pending a few previews. You saw it in lame-o-vision last week...

00:15

...but now it's going to be in all three dimensions, comin' at ya.

00:19

Suddenly, there they are - those terrifying triangles.

00:22

Only, they're not triangles anymore... They're prisms! Horrible, gory, flesh-eating

00:27

prisms. Ever seen light refracted through those glass

00:30

shapes to make a rainbow?

00:32

3D shapes have more than just length and width.

00:34

They have depth, too. Most 3D shapes you can make by gluing a bunch

00:39

of 2D shapes together. Be careful with the krazy-glue, though...

00:42

...you don't wanna walk around with a cylinder glued to your head.

00:45

A flat surface of a shape is called a face... ...the line that connects two faces is called

00:54

an edge... ...and a point on a 3D shape is called a vertex.

01:03

Prisms are two parallel polygons called bases with a bunch of lateral faces that connect

01:08

them. They're named after the shape of their bases,

01:11

so we could have... ...triangular prisms or...

01:15

...hexagonal prisms. Cylinders are like prisms, only the bases

01:19

are circles instead. Pyramids are like prisms, but with only one

01:26

base. And cones are pyramids with circular bases.

01:31

Spheres are like balls... but don't try playing basketball with one.

01:37

They're not regulation. Those are the basic three-dimensional shapes,

01:40

and the ones you'll probably see often. There are other ones like polyhedrons, but

01:45

we won't blow your mind any more for the time being.

01:48

Now that you've got a grip on basic 3D geometry... ...you can sit back, relax, and enjoy Revenge

01:54

of the Triangles... in 3D...

01:57

...or... try to.

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