Question

2. Write the equation of a circle that has a diameter of 12 units if its center is at (4,7).

O (x – 4)2 + (y – 7)2 = 144
O (x +4)2 + (y + 7)2 = 144
O (x – 4)2 + (y-7)2 = 36
O (x+4)2 + (y + 7)2 = 36

Answer 1

The Answer is B

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 diameter = 12, thus radius = 12 ÷ 2 = 6 and (h, k) = (2.5, - 3.5), thus

(x - 2.5)² + (y - (- 3.5))² = 6², that is

(x - 2.5)² + (y + 3.5)² = 36 ← equation of circle