Set the two fractions equal to each other
18/24 = 6/x
Cross multiply
18(x) = 6(24)
Simplify
18x = 144
Isolate the x, divide 18 from both sides
18x/18 = 144/18
x = 144/18
x = 8
Now find the area of each parallelogram.
18 x 24 = 432
6 x 8 = 48
Divide the two areas together
432/48 = 9
Note that Parallelogram ABCD is first.
9:1, or D, is your answer.
hope this helps