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Circles Videos 25 videos
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."
Equations of circles are a no-brainer. If aliens can do it, so can you. All you do is substitute the center of the circle's coordinates into the eq...
ACT Math 5.4 Plane Geometry 294 Views
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Description:
ACT Math: Plane Geometry Drill 5, Problem 4. What is the radius and coordinate center of the circle?
Transcript
- 00:02
Here's your shmoop du jour.
- 00:05
What is the radius and coordinate center of the circle: 25 = (x - 2) squared + (y + 2) squared?
- 00:15
And here are your options...
- 00:19
OK, here's the deal. When a circle is expressed in the form of the formula above, the radius
- 00:25
is always the square root of the integer to the left...
Full Transcript
- 00:29
that means that the radius is the square root of 25, which is 5.
- 00:34
And the coordinates of the center are the numbers in the x and y parentheses.
- 00:38
The trick for the coordinates is that you have to flip around the positives and negatives
- 00:42
from what's in the parentheses. Since the circle here has x minus two and
- 00:50
y plus two, the coordinates are positive 2 and negative two.
- 00:55
So our answer is just B.
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