Thanks for the query.
Let us consider that the sides of the polygons are in the ratio of 1 : k
Then their areas will be in the ratio 1 : k^2
Their perimeter will be in the ratio 1 : k
Therefore, 1 / k = 12 / 18
k = 3 / 2
Hence Area of polygon 1 + Area of polygon 2
= Area of polygon 1 + k^2 * Area of polygon 1 (since the Areas are in the ratio of 1 : k^2)
=> Area of polygon 1 + (9 / 4)* Area of polygon 1 = 65
Solving we get Area of polygon 1 >>> 20 sq units
and Area of polygon 2 >>> 20*(9 / 4) = 45 sq. units