Two poles are connected by a wire that is also connected to the ground. The first pole is 20 ft tall and the second pole is 10 ft tall. There is a distance of 30 ft between the two poles. Where should the wire be anchored to the ground to minimize the amount of wire need

Therefore the wire should be anchored at 10 ft away from pole which is 10 ft long.

Step-by-step explanation:

Given that , The distance between two poles is 30 ft.

The length of 1st pole is = 20 ft

The length of second pole is = 10 ft.

Let the wire anchored to the ground at a distance x ft from the second pole.

Then, the distance of anchored from the first pole is = (30-x)

The total length of the wire is L = m+n

We know the pythagorean theorem,

Height²+base² = hypotenuse²

To find the value of m and n we use  pythagorean theorem

From the left side triangle in the picture we get,

10²+x²= m²

⇒m²=100+x²

and right side  triangle in the picture we get,

20²+(30-x)² = n²

⇒n²= x²-60x+1300

Then ,

Differentiating with respect to x

For minimize, L' =0

Squaring both sides

Therefore x = 10. [x=-30 negligible, since distance can not negative]

Therefore the wire should be anchored at 10 ft away from pole which is 10 ft long.