Print out a copy of your picture of the moon, which you should still have open in a new window and label as many craters and Maria as possible.
Note: the scales will only work if the crater is towards the center of the Moon. The further out you go the greater the distortion of the features which we are viewing from an angle.
Craters are in the region of 10 times larger than the meteor or comet that caused them how big was the body involved in your impact with the moon?