A circle has a radius of √37 ​units and is centered at (1.3,−3.5 ). write the equation of this circle.

Question

I dont know how to write the equation.

Answer 1

(x-1.3)^2 + (y+3.5)^2 = 37

 

In general, (x-c)^2 + (y-k)^2 = r^2   where (c,k) is the center and r is the radius.

 

So if the circle with radius 5 has center (3,-4) then it's equation is:

   (x-3)^2 + (y+4)^2 = 25

 

Notice that the second term is (y+4)^2 because the y-coordinate is -4 and y-(-4) = y+4