400
Liang got an answer of about 3.67 when she entered 15 on her calculator and then pressed the square root key. As usual, she stopped to think whether or not that was a reasonable answer? Is it? Why or why not?
What is yes, it is a reasonable answer because the square root is the opposite of squaring a number. 3 squared is 9 and 4 squared is 16. It only makes sense that the square root of 15 would be some where between 3 and 4