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.