Geometry/ Ratios: Solve and explain the steps of this math problem

The area of a rectangle is 192 square feet. The ratio of the width to the length is 3:4. Find the length and width.

Please explain how to find the answers. Thanks in advance.

The Area is 192
The length and breadth are 3x and 4x
The area of Rectangle is Length X breadth = 192
3x * 4x = 192
12 x^2 = 192
x^2 =192 /12 = 16
x = 4
So lenth is 12 and breadth is 16