Square units of area in a circle I'm studying for the GRE and came across the practice question quoted below. I'm having a hard time understanding the meaning of the words they're using. Could someone help me parse their language?

"The number of square units in the area of a circle '$X$' is equal to $16$ times the number of units in its circumference. What are the diameters of circles that could fit completely inside circle $X$?"

For reference, the answer is $64$, and the "explanation" is based on $\pi r^2 = 16(2\pi r).$
Thanks!

I'm currently doing this, and how I see the problem is:
$πr^2 = (2πr) * 16 $
If you solve this, r gives $32$, and since diameter $d = 2*r$, $d = 64$.
So, any circle with a lesser diameter fits in this circle $(d<64)$
