So my wife is making a flag replica out of wood.
We want it dimensionally correct.
So a real store bought flag is 58 1/2 inches long. Hers are 37 1/2. The store bought flags short stripes are 33". How long should hers be?

just

21.12" -

37.5 is 64% of 58.5 and 64% of 33 is 21.12"

Holy cow I was right.
thanks Jayme

think of it as proportions

a flag is 3x5 feet typically anything that work into that ratio 1.66 wider than tall

the height of the blue field is 1/2 the height of the flag

the total length of the flag is 1 1/2 times longer than the blue field

the blue field is 1.3 times longer than it is high

my flag is 36 tall by 60 wide
the blue field is 18x24

if I wanted to paint a giant flag on my garage and I new that I had 8 feet in height to work with.

I would know my blue field is going to be 48 inches high by 62.4 wide and my total flag is going to be 96x1.66= 159.36 inches

8 foot tall 13 feet 3 inches approximately

62.5 x 2.5 gets you very close to the 159 inches giving you good proportion only off by a little rounding

This one is not correct but I consider it to be more art.