The Shadow

25) If a 40-foot pole will cast a shadow that is 75 feet long, then how long
would the shadow be (at the same time) of a 6-foot man who is standing beside
that tree?

With this kind of problem, we can use a simple formula for showing
proportions; and of which is very easy to double-check our work.

        40           6
      -------  =  -------
        75           x


        40(x) = 6(75)  (Here we set up the formula for cross-multiplying.)

        40x = 450  (Multiplying gave us this product.)

        x = 11.25  (Dividing both sides by 40 gave us the value of x.)

Cross-multiply to double check:

        6 * 75 = 40 * 11.25

           450 = 450 

The products should always be the same between the two cross-multiplied pairs.