ShmoopTube

Where Monty Python meets your 10th grade teacher.

Search Thousands of Shmoop Videos


Math III Videos 103 videos

Unit Rate
20718 Views

Approximately 874 people per day wonder what a unit rate is. If you're one of them, check out our video on unit rates and how to use them. (We just...

Solving Proportions Using Cross Products
6802 Views

This video covers how to use cross products to solve for a missing number in a proportion by setting that proportion with a variable over the produ...

GED Math 2.4 Rational Numbers
190 Views

GED Math 2.4 Rational Numbers. Lucius's favorite restaurant is how many km from his home?

See All

Attributes of Circles 6372 Views


Share It!


Description:

This video can run circles around other videos about circles. Sir Cumference, of Round Table fame, explains all the properties of… well, circles. Whether you're looking for how the radius relates to the diameter or how to deal with pi (when you’re not eating it, that is), this video covers the basic attributes of our circular friends. Our rotund knight even hits on area and perimeter, too. En garde!

Language:
English Language
Subjects:

Transcript

00:00

Circles, a la Shmoop. Greetings, members of King Area’s Court!

00:11

I, Sir Cumference, am the one who suggested our great Round Table.

00:17

I know it's caused you all some issues in the past…

00:20

…but switching to a rectangular table would be a big mistake.

00:24

Let me tell you why, dear chaps. First, a circle has no corners, so if we have

00:29

to run suddenly off to battle…

00:31

…or to the loo…

00:32

…we won't hurt ourselves on the corners. While rectangles have two measurements: length

00:37

and width, circles have a radius and a diameter. A circle's radius is the distance from its

00:42

center to the outside…

00:44

… and its diameter is the distance from one side of the circle all the way to the

00:49

opposite side…

00:50

… or, simply put, 2 times its own radius. How much simpler could it be?

00:55

Not yet convinced? Well, the best thing about the Round Table

00:59

is all the pie that comes with it! I don't mean apple or pumpkin pie.

01:04

We can get those at the market. I mean “pi.” 3-point-1-4.

01:07

The Holy Grail of Numbers. For instance, the distance around the circle

01:12

depends on its radius as well as pi!

01:16

We simply plug in 2 times pi times the radius, and we get our Circumference.

01:23

We can also substitute the 2 and the radius with the circle’s diameter to get our circumference.

01:31

But if we're trying to calculate the area of a circle, we'll need pi too.

01:34

Pi times the radius squared will give us the Area of our circle.

01:39

In conclusion, pi makes the world go round. And if the world goes round, why shouldn't

01:45

our table?

Related Videos

Introduction to 3D Geometry
55503 Views

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...

Surface Area of Cylinders
14741 Views

Haven't you always wondered how much cardboard it takes to encase a trunk warmer for your pet elephant?

Perimeter of Irregular Shapes
4864 Views

Want to figure out the area and perimeter of irregular shapes? Break them down into regular shapes. For example, a flower can be broken down into s...

An Introduction to 3D Geometry
815 Views

Does thinking about 3D Geometry get you bent out of shape? Never fear! Watch this video and figure out some fun new shapes to bend back into. We're...

ACT Math 3.5 Plane Geometry
394 Views

ACT Math: Plane Geometry Drill 3, Problem 5. How long would it take for the wheel to make two rotations?