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Playlist ACT® Plane Geometry 25 videos
Math Plane Geometry: Drill 1, Problem 1. What does a straight angle measure?
ACT Math: Plane Geometry Drill 1, Problem 2. In the following diagram, what does Angle 2 measure?
ACT Math: Plane Geometry Drill 1, Problem 3. What does Angle 15 measure in the given diagram?
ACT Math 5.4 Plane Geometry 294 Views
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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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