What Is The Radius Of A Circle If The Center Is (-2,-1)

What is the radius of a Circle if the center is (-2,-1)

 

Answer: 0

Step-by-step explanation:

Given the standard form of a circle (x-h)^2 + (y-k)^2 = r^2

Substitute the given (x+2)^2 + (y+1)^2 = r^2

Then, expand x^2+y^2+4x+2y+5.

Since we are now in the form of x^2+y^2+Dx+Ey+F = 0 (General form), we can now find the value of r by using F in the equation (which is 5)

F = h^2+k^2-r^2

5 = (-2)^2 + (-1)^2 - r^2

5= (4) + (1) - r^2

5= 5 -r^2

r^2= 5-5

r^2= 0

sqrt of r= 0