What is the equation of a circle with center [tex]\((-3,-5)\)[/tex] and radius 4?

A. [tex]\((x-3)^2+(y-5)^2=16\)[/tex]

B. [tex]\((x+3)^2+(y+5)^2=16\)[/tex]

C. [tex]\((x+3)^2+(y+5)^2=4\)[/tex]

D. [tex]\((x-3)^2+(y-5)^2=4\)[/tex]



Answer :

To determine the equation of a circle, we use the standard form of the equation, which is:

[tex]\[ (x - h)^2 + (y - k)^2 = r^2 \][/tex]

where [tex]\((h, k)\)[/tex] represents the center of the circle and [tex]\(r\)[/tex] is the radius.

Given the problem:
- The center of the circle is [tex]\((-3, -5)\)[/tex].
- The radius of the circle is [tex]\(4\)[/tex].

Let's substitute these values into the standard equation.

1. Identify the center [tex]\((h, k)\)[/tex]:
Here, [tex]\(h = -3\)[/tex] and [tex]\(k = -5\)[/tex].

2. Identify the radius [tex]\(r\)[/tex]:
Here, [tex]\(r = 4\)[/tex].

3. Substitute values into the standard form:
[tex]\[ (x - (-3))^2 + (y - (-5))^2 = 4^2 \][/tex]

4. Simplify the minus signs:
[tex]\[ (x + 3)^2 + (y + 5)^2 = 16 \][/tex]

Therefore, the equation of the circle is:
[tex]\[ (x + 3)^2 + (y + 5)^2 = 16 \][/tex]

Now, let's match this equation with the given options.

A. [tex]\((x - 3)^2 + (y - 5)^2 = 16\)[/tex]

B. [tex]\((x + 3)^2 + (y + 5)^2 = 16\)[/tex]

C. [tex]\((x + 3)^2 + (y + 5)^2 = 4\)[/tex]

D. [tex]\((x - 3)^2 + (y - 5)^2 = 4\)[/tex]

The correct option is B:
[tex]\[ (x + 3)^2 + (y + 5)^2 = 16 \][/tex]

So, the correct answer is option B.