ok that is a good answer, we need the three, to my point of view you have spoke well ,knowledge is the ability to know something either by purpose or accidentally, you can aquire knowledge in any area at any time, but when we talk about understanding ,let me say this, in ranking they are greater than each other but they can never work without each other,like we are talking about the body in whole and we are asking which is greater among the part of the body,we know that the head is the most important but the head will have problem if any part of the body have problem so what am saying niw is that they are greater and important than each other but they can't really work well without each other.
when we talking about understanding, understanding is the ability to assimilate knowledge, hmmm,you cant call something knowledge or else you know it ,and what you don't understand you can't know it you only have idea or clue, before you can boast of knowing something you have to understand the thing,the reason why we have dull students in our school days is not because they do not have idea or clue of what the teacher is teaching but they don't know it because they find it difficult to take the full details into their memory for applications which is the process of understanding so they can also say they know it.
so we can say KNOWLEDGE is information or a theory and the ability to install it or aquire it is UNDERSTANDING. so this point you should know their level according to my explanation UNDERSTANDING is greater than KNOWLEDGE, so moving forward lets now talk about WISDOM,wisdom is the ability to use the knowledge that you understand in a perfect and upright manner, wisdom guides your decision, you can only be wise base on your decisions,one of the reason why wisdom is the greatest is because sometimes its a matter of life and death it is left to your decision and judgement