Question

1. Which is the equation of a circle with center (–2, 3) and radius r = 5?
(x + 2)² + (y – 3)² = 10
(x + 2)² + (y – 3)² = 25
(x – 2)² + (y + 3)² = 10
(x – 2)² + (y + 3)² = 25

2. A circle with center (–1, 2) passes through point (2, –2). Which is true?

The radius is.
The diameter is 10.
The equation is (x + 1)² + (y – 2)² = 10.
The circumference is 25.
4. Which is the equation of a circle with diameterwith A(5, 4) and B(–1, –4)?
(x – 5)² + (y – 4)² = 10
(x + 5)² + (y + 4)² = 100
(x – 2)² + y² = 25
(x + 2)² + y² = 5

Answer 1

In the equation of a circle:
\[(x-h)^2+(y-k)^2=r^2\]
What does (h,k) represent? What does r represent?

Answer 2

Don't you have a book?

Answer 3

(h,k) is the center. r is the radius. So in your first example,
\[(x+2)^2+(y-3)^2=10\]
We would rewrite that like this so that it fits the form I posted:
\[(x--2)^2+(y-3)^2=(\sqrt{10})^2\]

So now we see that h is -2, k is 3 and r is sqrt(10)
That means that the center of the circle is (-2,3) and the radius is sqrt(10)
What is the center and radius of the second choice?

Answer 4

Close but not quite.

Answer 5

is it (x-2)+(y+3)=25

Answer 6

Use the distance formula to find the radius.

Answer 7

hey do you have the answers to the other questions?

Answer 8

Did anyone get these ??

Answer 9

Heyy! Did anyone get the second or third ont here?? @Danielle96 @Azteck