<span>The figure shown
below is an example of ratio and proportion. A ratio is a comparison between
two different things. A proportion is two ratios that have been set equal to
each other. Note that in the figure shown below, the form and angle of quadilateral ABCD is similar to quadilateral
EFGD. So if we have angle ABC, it is proportional to angle EFG or angle
E. From the question, angle CGF is proportional to angle GDE or angle D.</span>
It wants you to mark "Angle D", because Angle-D is equal to angle-CGF ... they're the same size.
But they are not "corresponding" angles.
Angle-CGF is an angle outside of the smaller figure. The corresponding angle of the larger figure would be the angle above and outside of corner-C, if the side DC were extended a little bit to make an angle up there.
