# help in this math project

• April 15th 2008, 06:03 PM
help in this math project
help would be appreciated if u can solve it all i will be very thankful and i would like some hints too
• April 16th 2008, 12:20 AM
Mathnasium
What have you done so far? Where are you stuck? What formulas do you know about circles?
• April 16th 2008, 04:38 AM
skystar
The equation of a circle is $(x-a)^2 + (y-b)^2 = r^2$

where $(a,b)$ is the centre of the circle and r the radius.
• April 16th 2008, 07:00 AM
Aryth
$x^2 + y^2 - 2x - 4y - 4 = 0$

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

Complete the square for both:

$(x^2 - 2x + 1) + (y^2 - 4y + 4) = 9$

Now we factor:

$(x - 1)^2 + (y - 2)^2 = 3^2$

Therefore, r = 3 and the center is $(1, 2)$