Is this a question of perspectives? Like, the closer the object gets the bigger it appears? (And thus, the 10cm 'diameter' is a relative measurement, not an absolute one?
>>368720
If the answer is yes, then it's just a proportions thing... W1/D1 = W2/D2
So 10cm / 91.5 cm = x / 91 cm...
x = 9.84 cm
right object is 10.33 cm.
>>368704
Apparent size at distance X = [apparent size at reference distance]*( [reference distance]/[distance X] )
You can use this to calculate the apparent size of any object at any distance