A square has an area of 100 cm2. What is the length of one side of the square?
Draw a square. Tracing a pad of Post-It notes works like a charm if your freehand lines are a little shaky. Label the side length s (or x, or y, or @, or whatever variable you like). We can see that the area A of the square is given by this formula:
A = s2
Because A is 100, we find the answers if we solve the formula.
100 = s2
s = ±10
However, the answer -10 doesn't make any sense in the context of this problem. What are negative centimeters? The metric system may seem a little weird to many of us, but it's not that weird. A good way to show work here would be to write something like this sentence:
"Since the length of a side can't be negative, we can eliminate the answer s = -10. The final answer is s = 10 cm." Then sit back, cross your arms, and wait for the extra credit and accolades to come rolling in.