Need help calculating

hi- I’m making a baby blanket for my sister, and I want it to be 30" long. I did a swatch of 20 stitches which equalled 3.75". So for it to be 30" I did the following calculation

30/3.75 = 8
8*20= 160

is this correct for my blanket to be 30" across?
any help would be greatly appreciated

I do it a little different but you are right! I divided 20 by 3.75 and came up with 5.3 and multiplied it by 30 equaling 159.9999999999 Looks like 160 to me! Mary

The beauty of math (oh my gosh did I just say that???) is that there are usually more than one way to arrive at the answer.

LOL!!! At age 15 with a D average in algebra, I just knew I would never need to use the principles of “pie r square” but I became a seamstress, working now reupholstering marine furniture and a knitter and I use it constantly. Math IS a wonderful (did I say that?) thing.