Question

what is the radius of a circle with the equation x^2+y^2+2x+4y-9=0?

Answer 1

\(x^2+2x+y^2+4y-9=0\\(x+1)^2-1+(y+2)^2-4-9=0\\(x+1)^2+(y+2)^2=14\)

Answer 2

so the radius is 14?

Answer 3

now use the equation of a circle to get the radius

I completed the square two times...

Answer 4

http://www.purplemath.com/modules/sqrcircle.htm

Answer 5

what is the equation of a circle?

Answer 6

check that link

Answer 7

(x+h)^2+(y-k)^2=r^2

Answer 8

so we have r^2 = 14
what is r?

Answer 9

\[\sqrt{14}\]

Answer 10

it is important that you see how I did this problem, do you?

Answer 11

i guess its sqrt(14)

Answer 12

or 196

Answer 13

what is 196?

Answer 14

nevermind i guess its square root of 14 but it also says to put the answer into the nearest thousand form

Answer 15

so is it 3.472 ?

Answer 16

if thats what your calculator says...