What is the radius of a circle whose equation is x2+y2+8x−6y+21=0?

The radius is 2 units.

Step-by-step explanation:

x^2 + y^2 + 8x − 6y + 21 = 0

Convert this to the general form (x - a)^2 + (y - b)^2 = r^2 by completing the square:

We have:

x^2 + 8x + y^2 - 6y = -21

(x + 4)^2 - 16 + (y - 3)^2 - 9 = -21

(x + 4)^2 + (y - 3)^2 = 4

Comparing with the above general form we see that

r^2 = 4

and therefore r = 2.

answer: the answer is (b) amie should have multiplied

step-by-step explanation: given a sphere and a cylinder with same radius and height.

let, 'r' be the radius of the cylinder and sphere and 'h' be the height of the cylinder. according to the question,

r = h.

now, the volume of the sphere will be

and the volume of the cylinder will be

therefore, we have

thus, ammie should have multiplied the volume of the sphere

the radius is 2 times the diameter.

step-by-step explanation: