Question

A guy wire attached to a vertical pole of height $18$ m is $24$ m long and has a stake attached to the other end How far from the base of the pole should the stake be driven so that the wife will be taut ?

• A. $6\sqrt{7}cm$
• B. $5\sqrt{7}cm$
• C. $4\sqrt{7}cm$
• D. $3\sqrt{7}cm$

Answer 1

The correct option is A $6\sqrt{7}cm$

Let AB ($=24m$ ) be guy wire attached to a vertical pole BC of height 18 m. To keep the wire taut let it fixed to stake at A Then ABC is a right triangle right angled at C
$\therefore A{B}^2=A{C}^2+B{C}^2$
so $\therefore {24}^2=A{C}^2+{18}^2$
or $A{C}^2=576-324$
or $A{C}^2=252$
or $AC=\sqrt{252}$
$=6\sqrt{7}cm$
therefore the stake may be placed at a distance of $6\sqrt{7}m$ from the base of pole