the flag is right angle triangle,
it base = 8 in
hypotenuse = 10 in
we know the Pythagoras theorem,


take root both side,

so the perimeter of the flag is, = sum of all sides
6 + 8 + 10 = 24 inches,
For the Canon mouth,
it has the shape of circle,
so, radius is r = 9 in
the circumference is,


so the circumference of the canon's mouth is 56.57 inches,
thus, canon's mouth circumference is greater than the perimeter of the flag