The ratio of the areas of two concentric circles is 1:3. If the radius of the smaller is r, then the difference between the radii is best approximated by:
<spanclass=′latex−bold′>(A)</span>0.41r<spanclass=′latex−bold′>(B)</span>0.73<spanclass=′latex−bold′>(C)</span>0.75<spanclass=′latex−bold′>(D)</span>0.73r<spanclass=′latex−bold′>(E)</span>0.75r