# Math Help - help in this math project

1. ## 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

2. What have you done so far? Where are you stuck? What formulas do you know about circles?

3. 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.

4. $x^2 + y^2 - 2x - 4y - 4 = 0$

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

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 $(1, 2)$