If 62 is divided by 47 we get a percentage of 32%. Oystein maintains that the length of the craft must be increased by 32% to get the real length of the craft but this is incorrect as the above proof shows that the distance between the 47mm mark and the 62mm mark on a line is 24%–not 32%.
Where did Oystein say this? Have another look at posts 214 and 215, and quote Oystein directly if you can!
Oystein's workings were very clear, elegant, and easy to follow in my opinion: in the security camera photo, the plane would appear only 57% of the length it would have appeared had it been ordinated perpendicular to the line-of-sight. I think your 24% and 32% figures are a red-herring; although I'd be happy to read a mathematical proof of why dividing the length of line BD by the length of line CD (or vice versa) would give you the effective foreshortening of the plane. Looks like a crock to me.
Like you, I haven't done much trig lately, but this is what I came up with after a few minutes on Google (any corrections welcome):
* Paste the overhead Google Earth image into Paint (
link).
* Take two coordinates on both the line-of-sight and the flight-path (by hovering the cursor).
* Assuming you don't know how to do this; (2101,827) and (369,542) were on the line-of-sight; and (2721,1349) and (1518,234) were on the flight-path.
* Find the gradient of each line (m1 and m2) by dividing the change in the y coordinate by the change in the x coordinate (
link).
* Assuming you don't understand this step; I got gradients of 0.16455 (line-of-sight); and 0.92685 (flight-path).
* Find the angle between the 2 lines using the formula tan(A) = (m1 x m2) / (1 + [m1 x m2]) (
link).
* Assuming you don't understand this step; I got an angle of 33.19204 degrees.
* So we now have a notional triangle and we want to know the ratio between the opposite length (the effective length of the plane from our line-of-sight) and the hypotenuse (the actual length of the plane).
* Sin (33.19204) x 100 = 55%, rounded up (
link) - this is, very roughly, the effective length of the plane (close enough to Oystein's figure of 57%; way more than your 24 or 32%).
* Conclusion: following a different method, and using different measurements, I confirmed Oystein's conclusion that the plane would appear approximately 57% of the length it would have appeared had it been ordinated perpendicular to the line-of-sight.
Prediction: accusation of obfuscation, and insistence that 24% is still correct, without the necessary smarts to prove it. Truth-seeker?