What would be the area of a pinhead one sixteenth of an inch across?

Assuming it is a round pinhead, this is a circle 1/16 inch diameter.

Formula for area of a circle is PI x Diameter squared/4.

Therefore calculation is 3.124 x 1/16 x 1/16 x1/4 square inches.

Answer = 0.00305 square inches. Remember the formula for next time!