Question

a large Elm tree died after it was struck by lightning. The property owner thinks he can remove it himself, but it’s concerned that it will fall on his greenhouse. He takes several measurements before attempting to cut it down. At 3 PM he measures the shadow of the tree and phonic to be 15 feet long. he also determines that the tree is 27 feet from the greenhouse. What else must he know to be able to determine the height of the tree?

Answer 1

To determine the height of the tree using the measurements he has taken, the property owner needs to know the angle of elevation of the sun at the time he measured the shadow. Specifically, he can use trigonometric relationships to calculate the height of the tree if he knows this angle.

The relationship can be set up using the tangent function from trigonometry, which relates the height of the tree (h) to the length of the shadow (s) and the angle of elevation (θ) of the sun:

\[
\tan(θ) = \frac{h}{s}
\]

Where:
- \( h \) is the height of the tree,
- \( s \) is the length of the shadow (15 feet),
- \( θ \) is the angle of elevation of the sun.

Once he knows the angle of elevation, he can rearrange the equation to solve for \( h \):

\[
h = s \cdot \tan(θ)
\]

In summary, to determine the height of the tree, the property owner needs to know the angle of elevation of the sun at the time he took the measurements.