Find the angular size of a circular object with a 4-inch diameter viewed from a distance of 5 yards.
+128460 5 yards = 180 in
We have a right triangle with a hypotenuse drawn from the vantage point to the center of the circle = (2 in + 180 in) = 182 in and a leg of 2 in which meets a tangent drawn to the circle from the vantage point
We can use the arcsin function to find (1/2) of the measure of the angle we need......so we have
arcsin (2/182) = θ ≈ .63°
So....twice the measure of this angle is what we need ≈ 1.26°
