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42 votes
If anyone knows the answer plz tell me, thank you

If anyone knows the answer plz tell me, thank you-example-1
User Leucos
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2 Answers

16 votes
16 votes

Answer:


\text{A) }x^2+y^2=25

Explanation:

The equation of a circle with center
(h, k) and radius
r is given by:


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

We're given:

  • The circle's center is at the origin (0, 0)
  • The point (-3, 4) is on the circle

Since we're given the circle's center, we just need to find the radius. Because the center of the circle is at (0, 0), the radius will be equal to the distance from (-3, 4) and (0, 0).

For points
(x_1, x_2) and
(x_2, y_2), the distance between them is given by the formula:


d=√((x_2-x_1)^2+(y_2-y_1)^2)

Let:


(x_1, y_1)\implies (0, 0)\\(x_2, y_2)\implies (-3, 4)

The distance between these two points must be:


d=√((-3-0)^2+(4-0)^2),\\d=√(9+16),\\d=√(25),\\d=5

Therefore, the radius of the circle is 5 and the equation of the circle is:


(x-0)^2+(y-0)^2=5^2,\\\boxed{x^2+y^2=25}

User Thupten
by
3.2k points
15 votes
15 votes

Answer:

A

Explanation:

plug it in

(-3)^2+(4)^2=9+16=25

User PeaGon
by
2.9k points