the sun is a source of light / light energy called sunlight & as a source of light moves directly overhead of an object , the size of the shadow of that object will decrease ->  when the sun moves directly overhead of an object, the size of the shadow of that object will be the smallest  when the sun moves directly overhead of an object, the size of the shadow of that object will be the smallest & the sun is located directly overhead at noon ->  the shadows of an object at noon will be the smallest  the shadows of an object at noon will be the smallest & a flagpole is a kind of object -> the shadow of a flagpole will be the smallest at noon