# How do you identify the center and the radius of a circle with the equation #(x + 5)^2 + (y + 3)^2 = 49#?

##### 1 Answer

Jan 19, 2016

#### Answer:

centre = ( - 5 , - 3 ) and radius = 7

#### Explanation:

The standard form of the equation of a circle is:

#(x - a )^2 + (y - b )^2 = r^2 # where (a , b ) are the coordinates of the centre and r is radius.

compare

# (x + 5 )^2 + (y + 3 )^2 =49 # with standard forma = -5 and b = - 3 hence centre = ( - 5 , - 3 )

and

# r^2 = 49 rArr r = sqrt49 = 7 #