(a) From a reliable source, obtain the distance between Mars and the Sun.  How 
many radians of arc does the Sun subtend, as observed from Mars?  Express your 
answer in terms of degrees, and in arcseconds.

(b) Now measure the distance from your eye to your outstretched hand, and the 
diameter of a dime.  How much larger or smaller would the Sun appear from Mars 
compared to a dime held at your arm's length?