Question

From my act prep guide I need this practice problem answeredcalc subject

Answer 1

The standard form of the equation of a circle with centre (a,b) and radius r, is:

$(x-a)^2+(y-b)^2=r^2$

From the question, we provided with the following;

$\begin{gathered} \text{diameter}=8\text{units} \\ \text{ Recall that:} \\ \text{Radius}=\frac{diameter}{2} \\ R=\frac{8}{2}=4\text{units} \\ \\ \text{Centre (a,b)=(2,-4)} \end{gathered}$

Thus, we have:

$\begin{gathered} (x-2)^2+(y-(-4))^2=4^2 \\ (x-2)^2+(y+4)^2=16 \end{gathered}$

Hence, the equation of the circle is:

$(x-2)^2+(y+4)^2=16$