Answer: 12 3/8
10 1/2 + 10 1/2= 21
45 3/4 - 21 = 24 3/4
24 ÷ 2 = 12
Change the 3/4 into 8ths = 6/8
Divide that in half which gives you 3/8
So the length is 12 3/8
Probably a for plot, because It shows how close each value is, or if the values are all scattered around. it gives you a more accurate ways of seeing how close the data is. hope this helped