To find the length of the distance from the tip of the silo to the shadow, you have to use the Pythagorean theorem. Both the silo and the shadow are the legs of the triangle. So they go into the a and B of the formula:
a^2+b^2=c^2
16^2+12^2=c^2
256+144=c^2
400=c^2
20=c
So the distance from the tip of the silo to the shadow is 20 ft.
