Today I was sitting in the library. I had gotten some studying done, but was not planning to leave. I planned to stay for at least 3 more hours. But I came across a problem, realized something, felt I had lost my mind, and so came back home. I learned the formula for the area of a square in like 5th grade. Now I'm an undergraduate freshman, weeks form finishing my first year. I have known the formula for the area of a square for the past 8 years or so. Today I was going through a physics problems. Like (what I assumed to have done a million times before), I converted the dimensions of a rectangle from centimeters to meters, and went on to find the magnetic flux. I needed to find the area of the rectangle for that. The dimensions were 15 cm and 10 cm. And I got .15 m and .10m. I multiplied the two dimensions, and realized that I couldn't do that because the area was smaller than each dimension. I thought I had lost my mind. I couldn't believe this. How could I have not realized this before. I've been doing this for so long, I've done this so many times. How can it be that I didn't realize this until now? How come when I was taught the formula for finding the area of a circle, I wasn't told the domain was restricted to be greater than or equal to +1. What is going on? How can I be so far behind? What else don't I know? How do I find the area of a square with side 0.1m? Please help me.