Find the angular size of a circular object with a 3-inch diameter viewed from a distance of 9 yards.
Solution:-
The formula for angular size is shown below.
Angular size = physical size *
Note that the physical size of the object (its diameter) is given inches, while the viewing distance is given in yards. Convert the viewing distance to inches.
1 yard = 36 inches
8 yards = 288 inches
Substitute into the formula.
Angular size = (3 in)*
Perform the calculations.
angular size = 
=
= 