The top box on the page explains the idea completely. You need to read the top box several times, and understand it. A ratio is a comparison of two quantities by division.
1). Days in May: 31 Days in a year: 365 Their ratio: 31/365 .
2). Sides of a triangle: 3 Sides of a square: 4 Their ratio: 3/4 .
The middle box explains how two ratios can be equal, and it gives you a very detailed example. You should read the middle box and understand it. Ratios are fractions. They can be equal in just the same way that any two fractions can be equal. And you can simplify ratios in exactly the same way that you simplify fractions ... divide top and bottom both by the same number.
3). 8/12 Cook up three equal ratios. 1. divide top and bottom by 2 . . . . . 4/6 2. divide top and bottom by 4 . . . . . 2/3 3. multiply top and bottom by 9 . . . . 72/108 These are just some that I chose. There are millions of others.
4). 20/25 Cook up three equal ratios. 1. divide top and bottom by 5 . . . . . 4/5 2. multiply top and bottom by 4 . . . . 80/100 3. multiply top and bottom by 3 . . . . 60/75 These are just some that I chose. There are millions of others.
5). 5/6 Cook up three equal ratios. 1. multiply top and bottom by 2 . . . . 10/12 2. multiply top and bottom by 3 . . . . 3. multiply top and bottom by 9 . . . . 45/54 These are just some that I chose. There are millions of others.
6). 10/14 Cook up three equal ratios. 1. divide top and bottom by 2 . . . . 5/7 2. multiply top and bottom by 2 . . . . 3. multiply top and bottom by (you choose) . . . .
You can use a graphing calculator like desmos or draw your own graph to figure this out. Start by graphing each of those points. Then count the width and height. Multiply them to get the area. The width and height of the rectangle were 6 and 8, so the area is 48