The american flag is customarily made with its width and length in the ratio of 10 to 19. which of the following dimensions is in the correct ratio for the flag?

You have not provided the options, therefore, I cannot give an exact answer. However, I can help you with the procedures.

We are given that the ratio between the width and the length of the flag is 10 to 19.
This means that:


Therefore, to get the correct choice, all you have to do is divide the width by the length, if the result is 10/19, then the dimensions given are correct.

Examples:
For length = 190 and width = 100,
width / length = 100 / 190 = 10 / 19 .........> correct choice

For length = 1.9 and width = 1,
width / length = 1 / 1.9 = 10 / 19 .......> correct choice

Hope this helps :)

C, e, and a (hope it )