Identify the equation of the circle that has its center at [tex]\((9,12)\)[/tex] and passes through the origin.

A. [tex]\((x+9)^2+(y+12)^2=225\)[/tex]
B. [tex]\((x+9)^2+(y+12)^2=15\)[/tex]
C. [tex]\((x-9)^2+(y-12)^2=15\)[/tex]
D. [tex]\((x-9)^2+(y-12)^2=225\)[/tex]



Answer :

To identify the equation of the circle that has its center at [tex]\((9, 12)\)[/tex] and passes through the origin [tex]\((0, 0)\)[/tex], follow these steps:

1. Determine the Center and a Point on the Circle:

Given:
- Center of the circle [tex]\((h, k)\)[/tex] is [tex]\((9, 12)\)[/tex].
- The circle passes through the origin [tex]\((0, 0)\)[/tex].

2. Calculate the Radius of the Circle:

The radius [tex]\(r\)[/tex] of the circle can be found using the distance formula between the center [tex]\((9, 12)\)[/tex] and the origin [tex]\((0, 0)\)[/tex]:
[tex]\[ r = \sqrt{(x_1 - h)^2 + (y_1 - k)^2} \][/tex]
Substitute the values:
[tex]\[ r = \sqrt{(0 - 9)^2 + (0 - 12)^2} = \sqrt{81 + 144} = \sqrt{225} = 15 \][/tex]

3. Formulate the Equation of the Circle:

The standard form of the equation of a circle with center [tex]\((h, k)\)[/tex] and radius [tex]\(r\)[/tex] is:
[tex]\[ (x - h)^2 + (y - k)^2 = r^2 \][/tex]
Substitute [tex]\(h = 9\)[/tex], [tex]\(k = 12\)[/tex], and [tex]\(r = 15\)[/tex]:
[tex]\[ (x - 9)^2 + (y - 12)^2 = 15^2 \][/tex]
Which simplifies to:
[tex]\[ (x - 9)^2 + (y - 12)^2 = 225 \][/tex]

4. Identify the Correct Equation from Given Options:

Among the given options, the correct equation is:
[tex]\[ \text{D.}\ (x - 9)^2 + (y - 12)^2 = 225 \][/tex]

Hence, the equation of the circle that has its center at [tex]\((9, 12)\)[/tex] and passes through the origin is:

Option D. [tex]\((x - 9)^2 + (y - 12)^2 = 225\)[/tex]