Acompany that manufactures toy trains is making a new boxcar. to fit on the track, the smallest dimension of the toy boxcar must be 2 inches. what should be the length and height of the toy if the company wants the toy boxcar to be geometrically similar to an actual boxcar with the dimensions shown?

answer: 4  

the square root of 16 is 4. it is a very simple mathematic concept. a square root when a number multiplied by itself will result in a number. here, the number 16 comes when 4 is multiplied by 4. hence the square root of 16 is 4. you can always figure out a square root by the inverse operation of squaring.  

we need to divide the number of toy dinosaurs, 156, by the number of brothers, 4:

in order to estimate, we can use compatible numbers:

156 ÷ 4

  ↓

160   ÷ 4 = 40        

the correct answer is a).