Question

Circle T is defined by the equation (x + 5)2 + (y - 2) = 81. Which of the following shows the location of the center of Circle T and the radius of this

circle?
A T is located on (-5, 2); radius = 9 units
B T is located at (5,-2); radius = 9 units
C T is located at (-5, 2); radius = 81 units
D T is located at (5,-2); radius = 81 units

Answer 1

A) T is located on (-5, 2); radius = 9 units

Explanation:

eqn of circle= (x-a)^2 + (y-b)^2 = r^2

where (a,b) is centre of circle.

(x+5)^2 = (x - (-5) )^2

(y-2)^2 = (y - (2) )^2

(-5,2)

r^2 =81

r = sqrt of 81

r = 9