Question

A man who is 70 inches tall has a shadow that is 80 inches long. A nearby tree casts a shadow that is 164 inches long. The shadow of the man and the shadow of the tree form similar triangles. How tall is the tree in inches?(1 point)

1 answer

To find the height of the tree, we can use the properties of similar triangles. Since the man and the tree cast shadows that are proportional, we can set up a proportion based on their heights and shadow lengths.

Let \( h \) be the height of the tree. The proportions from the similar triangles can be set up as follows:

\[ \frac{\text{Height of the man}}{\text{Length of the man's shadow}} = \frac{\text{Height of the tree}}{\text{Length of the tree's shadow}} \]

Now we can substitute in the known values:

\[ \frac{70}{80} = \frac{h}{164} \]

Now we will cross-multiply to solve for \( h \):

\[ 70 \cdot 164 = 80 \cdot h \]

Calculating \( 70 \cdot 164 \):

\[ 70 \cdot 164 = 11480 \]

Now the equation becomes:

\[ 11480 = 80h \]

Now, divide both sides by 80 to solve for \( h \):

\[ h = \frac{11480}{80} = 143.5 \]

Therefore, the height of the tree is \( \boxed{143.5} \) inches.