5px = 1.72m For the average human
400px = iku arm 400/5*1.72= 137.6m for the giants arm
34pix = 137.6m
81/34*137.6 = 327.8m
122/34*137.6 = 493.7m
655/34*137.6pix =2650.8m
For the modeling I used triangular prism forumla V=1/2b*l*h
V=141921127.092 which equates to 45902127617016000 joules which is 11 megatons or City level
Which came out pretty much the same outcome as before
For the high end I used the same forumla but scaled someone who was a bit closer to the giant, in this case they were about 2 pixels
2px = 1.72m
iku arm = 400px 400/2*1.72= 344m
34px = 344m
81/34*344 = 819.5m
122/34*344 = 1234.3m
647/34*344 = 6546.1m
V= 3310668466.05
708483051734700000 joules which is 169.3 megatons or Mountain level
The high end came out even more impressive than before which is surprising but should be in the range for the feat.