Question

HELP im lost!!! What is the radius of a circle given by the equation (x+1)^2+(y-2)^2=64

Answer 1

whats the general equation of a circle?

Answer 2

radius is 8

Answer 3

is it? how?

Answer 4

good question :)

Answer 5

the general equation of a circle is defined as:

x^2+y^2 = r^2

so that that last bit is the radius

Answer 6

if we compare this to what you have; that amounts to r^2 = 64; therefore r = 8

Answer 7

yea so do you square the radius at the end? just that?

Answer 8

yep; other equation might have to be worked INTO this form, but if they are already looking like this then the radius is the sqrt of the last bit

Answer 9

ooohhh ok

Answer 10

thank you i got it!:D

Answer 11

good ;)