A wire is stretched from the ground to the top of an antenna tower. The wire is 30 feet long. The height of the tower is 6 feet greater than the distance d from the towers base to the end of the wire. Find the distance d and the height of the tower

Answer :

The distance d is 18 feet.

The height of the tower is 24 feet.

Explanation:

The length of the wire is 30 feet.

The height of the tower is [tex](6+d)[/tex]

where d is the distance of the towers base to the end of the wire.

Using Pythagorean theorem, we have,

[tex](6+d)^{2}+d^{2}=30^{2}[/tex]

Simplifying, we have,

[tex]36+12 d+2 d^{2}=900[/tex]

[tex]2 d^{2}+12 d-864=0[/tex]

Using quadratic formula, we shall determine the value of d.

[tex]d=\frac{-12 \pm \sqrt{12^{2}-4 \cdot 2(-864)}}{2 \cdot 2}[/tex]

[tex]d=\frac{-12 \pm \sqrt{144+6912}}{4}[/tex]

[tex]d=\frac{-12 \pm \sqrt{7056}}{4}[/tex]

[tex]d=\frac{-12 \pm 84}{4}[/tex]

Thus, we have,

[tex]d=\frac{-12 + 84}{4}\\d=\frac{72}{4} \\d=18[/tex]  and   [tex]d=\frac{-12 - 84}{4}\\d=\frac{-96}{4} \\d=-24[/tex]

Since, the value of d cannot be negative.

Thus, [tex]d=18[/tex]

Hence, the distance from the tower's base to the end of the wire is 18 feet.

Substituting [tex]d=18[/tex] in [tex](6+d)[/tex], we get,

[tex]6+18=24[/tex]

Thus, the height of the tower is 24 feet.

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