# How do you write an equation of a circle with center (6,-9) and diameter = 2sqrt7?

##### 1 Answer

Jan 29, 2016

# ( x - 6 )^2 + (y+9)^2 = 7#

#### Explanation:

The standard form of the equation of a circle is :

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

The data required to complete the equation is given in this

question , centre (6 , - 9 ) and r =

# sqrt7 # hence equation is :

#( x - 6 )^2 + (y + 9 )^2 = (sqrt7)^2#