I can't see the length very well. I think it's 8 so I'll work with that.
If the figures are similar, then their sides are proportional.
Set up the proportion 8 is to 7 as x is to 3.
8/7 = x/3
Multiply the means and extremes.
7x = 24
x = 3.4
The correct answer is B. 3.4
Hope this helps =)
