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This video can run circles around other videos about circles. Sir Cumference, of Round Table fame, explains all the properties of… well, circles....
Time to learn about the area of a sector. And no, that's not the sector's bedroom with a bumper sticker on the door that reads, "GO AWAY."
It's super useful to be able to find the distance around stuff. Like when you’re being pursued by authorities while running around the base of an...
ACT Math 5.1 Plane Geometry 327 Views
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Description:
ACT Math: Plane Geometry Drill 5, Problem 1. What is the area of the circle?
Transcript
- 00:02
Time for your daily dose of Shmoop. This won't hurt a bit.
- 00:06
A circle has a circumference of 12π. What is the area of the circle?
- 00:10
And here are your options...
- 00:15
Okay, so we're given the circumference and we're looking for the area.
- 00:19
Hopefully, we remember the formula for the circumference of a circle: Diameter times pi
Full Transcript
- 00:19
Hopefully, we remember the formula for the circumference of a circle: Diameter times
- 00:24
We're told that a circle has a circumference
- 00:26
of 12 pi...which means the diameter of this circle is 12.
- 00:31
If the diameter is 12, the radius is exactly half of that... 6.
- 00:36
The area of a circle is equal to π times radius squared,
- 00:39
and now that we have the radius, we just have to plug in that value.
- 00:44
6 squared is 36...so we get 36π as our answer, which is choice C.
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This video can run circles around other videos about circles. Sir Cumference, of Round Table fame, explains all the properties of… well, circles....
Time to learn about the area of a sector. And no, that's not the sector's bedroom with a bumper sticker on the door that reads, "GO AWAY."