Question

Which equations represent circles that have a diameter of 12 units and a center that lies on the y-axis? Select two options. x2 + (y – 3)2 = 36 x2 + (y – 5)2 = 6 (x – 4)² + y² = 36 (x + 6)² + y² = 144 x2 + (y + 8)2 = 36

Answer 1

Explanation:

A circle with a diameter of 12 units and a center that lies on the y-axis would have an equation of the form:

(x - h)^2 + y^2 = r^2

where (h, 0) is the center of the circle, and r is the radius. We know that the diameter is 12 units, so the radius is half of that, which is 6 units.

Now we can check which of the given equations match this form:

x^2 + (y – 3)^2 = 36 : This is not in the required form, since the center is at (0, 3) and not on the y-axis.

x^2 + (y – 5)^2 = 6 : This is not in the required form, and also has a very small radius of sqrt(6), so it cannot have a diameter of 12 units.

(x – 4)² + y² = 36 : This is in the required form, with center at (4, 0), so it is a possible solution.

(x + 6)² + y² = 144 : This is in the required form, with center at (-6, 0), so it is also a possible solution.

x^2 + (y + 8)^2 = 36 : This is not in the required form, since the center is at (0, -8) and not on the y-axis.

Therefore, the two equations that represent circles with a diameter of 12 units and a center on the y-axis are:

(x – 4)² + y² = 36

(x + 6)² + y² = 144