Check the picture below.
you can pretty much count those lengths off the grid.
recall that A = 1/2 bh.
The answer of your question is 5% <span />
To be a gcf of a number, they have to all divide by it evenly
so if 2 is a gcf of 12 and 6 then 6/2=3 =whole and 12/2=6=whole so
therefor we can just introduct other factors which are not equal
just multiply 16 by 3 prime numbers or different numbers
16 times 2 =32
16 times 3=48
16 times 5=80
and that is an example
I believe C is correct,
Also, did you finish the equation for letter D?
16% porque all you have to do is multiply 40 by 4% 0.04