Question

 The area of a circle is less than 1 dm². Find the radius of the circle. The area of a circle is less than 1 dm². Find the radius of the circle.
it wants the answer to fit this:
The radius of the circle is less than _______ dm.

Answer 1

$\bf \textit{area of a circle}\\\\ A=\pi r^2\qquad \begin{cases} \textit{let's say the Area is 1 exactly}\\ A=1 \end{cases}\implies 1=\pi r^2 \\\\\\ \cfrac{1}{\sqrt{\pi }}=r$

if you drop the radius to less than that, then the Area will also drop to less than 1 unit, in this case it happens to be a decimeter