Question

A 6 ft adult has a shadow 3.6 ft long. How long is the shadow of a 5 ft child standing next to the adult?

Answer 1

Okay, this problem involves cross multiplying.

6 5
--- = ---
3.6 x

6 * x = 6x

3.6 * 5 = 18

Now, you divide.

6x = 18

6 cancels out.

What you do on one side, you do to the other, so now it's:

18 / 6 = 3

x = 3

So, if a 6 foot tall adult has a shadow of 3.6 feet long, then a child that is 5 feet tall has a shadow of 3 feet.

Answer 2

\[\Large \begin{array}{l}
\tan \theta = \frac{o}{a}\\
{\tan ^{ - 1}}\frac{{3.6}}{6} = 30.96^\circ \\
o = \tan \theta \cdot a = \tan 30.96 \cdot 5 \approx 3
\end{array}\]