A guy wire attached to a vertical pole of height 18 m is 24 m long has a stake attached to the other end. How far from the base of pole should the stake be driven so that the wire will be taut?
We will draw the figure from the given information as below,
Let AB be the vertical pole of length 18 m and let the stake be at the point C so the wire will be taut.
Therefore, we have $A B=18 \mathrm{~m}, A C=24 \mathrm{~m}$ and we have to find $\mathrm{BC}$.
Now we will use Pythagoras theorem,
$A C^{2}=A B^{2}+B C^{2}$
Let us substitute the values we get,
$24^{2}=18^{2}+B C^{2}$
$576=324+B C^{2}$
Subtracting 324 from both sides of the equation we get,
$B C^{2}=576-324$
$B C^{2}=252$
We can rewrite the 252 as $36 \times 7$, therefore, our equation becomes,
$B C^{2}=36 \times 7$
Now we will take the square root,
$B C=6 \times \sqrt{7}$
Therefore, the stake should be $6 \sqrt{7} \mathrm{~m}$ far from the base of the pole so that the wire will be taut.