The length of a rectangle is 60 in. and its width is 48 in. find the ratio of the length?

A ratio is two numbers, not just one. Look at a ruler. Some rulers have twelve marks, some have some other number, but you have to specify how many marks are on the ruler and how many of them measure the length. So if a ruler is marked in inches and your rectangle is 60 inches then you can say it is 60/12 of a foot, which happens to be the same as 5 feet. But if you only say 60, nobody knows what you are talking about. So a ratio always involves two numbers, and your question only specifies one number. That is like one hand clapping.

Get a ruler in your hands. Measure things until you start to understand how a ruler works. Measure some stuff and figure out where the center is. Say you measure a book and it's 7/8" thick. You look at your ruler and see that every eighth is divided into two sixteenths, so obviously half of 7/8" is going to be 7/16". If you write that out you have 1/2 x 7/8 = 7/16. And you notice that 1/2 is divided into 2/4 and then into 4/8 and so on, so you can convert anything to anything by multiplying all the numbers on top and then all the numbers on bottom.

Other rulers are divided into 10 and 100 parts. But an inch is still an inch, so anything on one ruler can be translated to the other ruler. A half inch on one ruler is 5/10 or 50/100 on the other. An eighth inch is just 12.5 marks when you have 100 marks per inch. A metric ruler divides an inch into 25.4 parts, so a half inch would be 12.7 of those parts. Pretty simple, isn't it? Practice this a bit and people will think you went to wizard school.