Question

(x + 1)2 + (y – 2)2 = 16
I'm suppose to find the radius and center of each circle, can someone please show me how?

Answer 1

the general form is
\[(x-h)^2+(y-k)^2=r^2\] for a circle with center at \((h,k)\) and radius \(r\)

Answer 2

ok so how do i find it?

Answer 3

match up the general to the specific to get your answer
\[(x-h)^2+(y-k)^2=r^2\\
(x+1)^2+(y-2)^2=4^2\]

Answer 4

your job is to identify \(h\), \(k\) and \(r\)

Answer 5

@satellite73 how?

Answer 6

pretty much with your eyeballs.
\[(x-\color{red}h)^2\\(x-\color{red}{(-1)})^2\] tells you \(\color{red} h =\color{red}{ -1}\)

Answer 7

\[(y-\color{blue}k)^2\\(y-\color{blue}2)^2\]
what is \(\color{blue}k\) ?

Answer 8

2

Answer 9

@satellite73

Answer 10

@Luigi0210 a little help please?

Answer 11

Use satellite's formula

Answer 12

yes, you are right, \(k=2\)

Answer 13

how do i find the radius?

Answer 14

and for the radius \[16=r^2\\
\color{green}4^2=\color{green}r^2\]\]

Answer 15

so \(\color{green}r=\color{green}?\)

Answer 16

4

Answer 17

ty!!!!!!!!!!!!!!!!!!!!!