Question

A Christmas tree is supported by a wire that is 9 meters longer than the height of the tree. The wire is anchored at a point whose distance from the base of the tree is 41 meters shorter than the height of the tree. What is the height of the tree

Answer 1

Answer:

The height of the tree is 80 meters.

Step-by-step explanation:

Let the height of the Christmas tree be x meters.

Then the length of the wire will be, (x + 9) meters.

And the wire will (x - 41) meters away from the base of the tree.

Consider the diagram below.

Use Pythagoras theorem to solve for x as follows:

$AB^{2}=AC^{2}+CB^{2}$

$(x+9)^{2}=x^{2}+(x-41)^{2}\\\\x^{2}+18x+81=x^{2}+x^{2}-82x+1681\\\\x^{2}-100x+1600=0\\\\x^{2} -80x-20x+1600=0\\\\x(x-80)-20(x-80)=0\\\\(x-80)(x-20)=0$

The value of x is either 80 or 20.

If x = 20, then the base CB will be -21. This is not possible as length is always positive.

Thus, the value of x is 80.

Hence, the height of the tree is 80 meters.