the product of sevan and a number increased by four equal to the product of twelve and the same number decreased by ten

Candy lives in the center of town. her friend darlene lives 28 miles to the east and her friend dana lives 21 miles north. approximately how far do dana and darline live apart ?

When solving this problem: 3025/5.5 = a/90.75 you get 49912.5 which would be the length of one of the sides of a square when the area is only 90.75 inches. is that answer correct, why, and how is it possible?

I’m still confused on how to work the percentages