Given slabs thicknesses 5in, 10in, and 15in.
Therefore,<u> </u><u>ratio of thicknesses in simplest form would be 1:2:3.</u>
Metal 1 thicknesses = 150lbs, 300lbs, 600lbs
Dividing by 150, we get ratio of Metal 1 thicknesses = 1:2:4.
Metal 2 thicknesses = 130lbs, 260lbs, 390lbs.
Dividing by 130, we get ratio of Metal 2 thicknesses = 1:2:3.
Metal 3 thicknesses = 310lbs, 620lbs, 930lbs.
Dividing by 310, we get ratio of Metal 3 thicknesses = 1:2:3.
Metal 4 thicknesses = 140lbs, 280lbs, 420lbs.
Dividing by 140, we get ratio of Metal 4 thicknesses = 1:2:3.
<u>We can see the ratios of thicknesses of Metal 1 are 1:2:4 but it should be 1:2:3.</u>
Therefore, Metal 1 weight is not proportional to thickness.