Question

Circle A is shown on the coordinates plane shown above

Answer 1

The center of the circle is at (-2, 0). The radius is 5 units. The equation for a circle, in standard form is

$(x-h)^2+(y-k)^2=r^2$.

We have our h and k from the center. h is the x coordinate and k is the y coordinate. The radius is 5. That means that the circle's equation, before simplifying, is

$(x-(-2))^2+(y-0)^2=5^2$. After simplifying it is

$(x+2)^2+y^2=25$. That's A and B. For C, we will simply pick points on the axes. One point on the circle is at (3, 0); another point is at (-2, 5); a third point is at (-7, 0). For D, the area of a circle is

$A=\pi r^2$.

For us that looks like this

$A=\pi (5)^2$. In terms of pi the answer is 25 pi, but in decimal form to the nearest square unit, it's 79 units squared.