"find the angular size of a circular object with a 1 inch diameter viewed from a distance of 2 yards"
I am assuming the simplest scenario.
Your body and the circle are in parallel planes. Your eye to the centre of the circle are at right angles to those planes.
start by considering an isosceles triangle, the circle diameter is one side (1 inch ), the other 2 equal sides mean at the centre of your eye.
Cut the isosceles triangle in half to make 2 right angled triangles.
Now the centre side is 2 yards = 72 inches long and each little side is 0.5 inch long.
Now use trigonometry to get half the required angle (that is, the little angle in one of the right angled triangles)
then duble it to get the whole angle.
Draw a picture to try and work out what I am saying. if you still need help post again and I will try to explain more.
+118654 
