### Home > CCA2 > Chapter 3 > Lesson 3.1.2 > Problem3-35

3-35.

Give the equation of each circle below in graphing form. .

1. A circle with radius of $12$ centered at the point $(−2, 13)$.

The general equation for a circle is: $(x−h)^2+(y−k)^2=r^2$.
What is $h$? $k$? $r$?

$(x+2)^2+(y−13)^2=144$

2. A circle with center $(−1, −4)$ and radius $1$.

$(x+1)^2+(y+4)^2=1$

3. A circle with equation $x^2 + y^2 − 6x + 16y + 57 = 0$ . (Hint: Complete the square for both $x$ and $y$.)

Rearrange the terms first:
$x^2-6x+$ _________ $+y^2+16y+$ _________ $=0+$ _________
Remember to add both numbers that complete the squares.

Use the eTool below to graph the equations for each part.
Click the link at right for the full version of the eTool: CCA2 3-35 HW eTool