Hi, I know that area of rectangle is length x breadth. I tried to find proof of area of rectangle but I found that the proof was solved by taking formula of area of square into consideration. But what I don't understand is why area of rectangle should be length times breadth, or side times side as in case of area of square. Question is: 1. How do I know that area of rectangle should be: length x breadth (what makes 'x' qualify for the formula of area of rectangle or square?) and not: length + breadth or anything else. 2. What is 'x' really? Thanks.