Question

What is the area of the circle whose equation is $(x-3{)}^2+(y+5{)}^2=18$?

• A. $9\pi$
• B. $18\pi$
• C. $72\pi$
• D. $81\pi$
• E. $324\pi$

Answer 1

The correct option is B $18\pi$

Given equation is $(x-3{)}^2+(y+5{)}^2=18$

The general equation of the circle $=$ $(x-h{)}^2+(y-k{)}^2=r^2$
From the equation, we can find the radius as $\sqrt{18}$
So, area of the circle $=$ $\pi r^2$
$=\pi (\sqrt{18}{)}^2$
$=18\pi$