Question

Write the equation of a circle centered at (-2,-8) with a diameter of 8.

Answer 1

(x + 2)² + (y + 8)² = 16

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

here (h, k ) = (- 2, - 8 ) and r = diameter ÷ 2 = 8 ÷ 2 = 4 , then

(x - (- 2) )² + (y - (- 8) )² = 4² , that is

(x + 2)² + (y + 8)² = 16