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The circle below is centered at the origin, and the length of its radius is 7. What is the circle's equation. A. 7x+7y=49. B. x^2+y^2=49. C. x^2+y^2=14.

User Lord Peter
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2 Answers

2 votes

Answer:

The equation of a circle is
x^(2) + y ^(2) = 49 .

Option (B) is correct .

Explanation:

The general equation of a circle is given by


(x - h)^(2) + (y - k)^(2) = r^(2)

Where (h,k) are the centre of the circle r is the radius of a circle.

As given

The circle is centered at the origin, and the length of its radius is 7.

(h,k) = (0,0)

r² = 49

Put in the equation of a circle.


(x - 0)^(2) + (y - 0)^(2) = 49


x^(2) + y ^(2) = 49

Therefore the equation of a circle is
x^(2) + y ^(2) = 49 .

Option (B) is correct .

The circle below is centered at the origin, and the length of its radius is 7. What-example-1
User Zac Brown
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8.6k points
2 votes
Equation of a circle is: (x−h)2+(y−k)2=r2 h is the x-coordinate of the center and k is the y-coordinate of the center. Even though the formula has minus signs, those are positive numbers. If there were plus signs in there, the numbers h and k would actually be negative. Now since you're centered at the origin, that means h and k are 0, so you'd just have this: x2+y2=r2 Now since your radius is 7, just square it and replace r^2 woth that value :)
User Gekkie
by
7.9k points

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