Question

What are the center and radius of the equation (x-2)^2 + (y-9)^2 = 36?

Answer 1

centre = (2, 9 ) , radius = 6

Explanation:

the equation of a circle in standard form is

(x - h)² + (y - k)² = r²

where (h, k ) are the coordinates of the centre and r is the radius

(x - 2)² + (y = 9)² = 36 ← is in standard form

with centre (2, 9 ) and r² = 36 ⇒ r =
`√(36)` = 6

Answer 2

center (2, 9); radius 6

Explanation:

Standard equation of a circle:

(x - h)² + (y - k)² = r²

where the center is (h, k), and r is the radius.

You have

(x - 2)² + (y - 9)² = 36

(x - 2)² + (y - 9)² = 6²

Compare this last form to

(x - h)² + (y - k)² = r²

h = 2; k = 9; r = 9

Answer: center (2, 9); radius 6