Editing Forced perspective (section)

===Calculating angular size===
[[File:Angular Size.jpg|thumb|alt=Angular Size depiction.|Angular size, distance and object size]]
The formula for calculating angular size is as follows:
:<math>\theta=2\cdot\arctan\frac{h}{2D}</math>

in which ''θ'' is the subtended angle, ''h'' is the actual size of the object and ''D'' is the distance from the lens to the object.<ref>Michael A. Seeds; Dana E. Backman (2010). Stars and Galaxies (7 ed.). Brooks Cole. p. 39.</ref>