An alien observer on Planet X can approximate distances in t

An alien observer on Planet X can approximate distances in the sky by using his \"hand\" at arm\'s length. An outstretched hand is about 30 arc degrees, a clenched fist is about 25 arc degrees, and a thumb corresponds to about 1 arc degree. If one clenched fist plus one outstretched hand covers the distance between two stars about how far apart in arc degrees are the stars? The apparent size of Moon X as observed from Planet X is about 21 arc minutes. Approximately what part of an observer\'s thumb would cover Moon X? Round to the nearest tenth as needed. 50 arc degrees; approximately 1/4 of a thumb 26 arc degrees; approximately 1/2 of a thumb 55 arc degrees; approximately 1/3 of a thumb 56 arc degrees; approximately 1/5 of a thumb

Solution

If one clenched fist plus one outstretched hand covers the distance between two stars

= 30+25 = 55 arc degrees

Size of Moon X = 21arc minutes = 21/60 arc degrees

So, Ratio of size of moon/size of thumb = 21/60*1 = 21/60 = 7/20 = 1/3

So, roughly 1/3 rd of a thumb

Option C