Math Problem Statement

Dalvin is 1.85 meters tall. At 3 p.m., he measures the length of a tree's shadow to be 31.35 meters. He stands 27.2 meters away from the tree, so that the tip of his shadow meets the tip of the tree's shadow. Find the height of the tree to the nearest hundredth of a meter.

Solution

This problem involves using similar triangles to find the height of the tree. Dalvin and the tree create two right triangles with their shadows as one side and their heights as the other.

Let's define the variables:

  • Dalvin's height: hD=1.85metersh_D = 1.85 \, \text{meters}
  • Dalvin's shadow length: sDmeterss_D \, \text{meters}
  • Tree's height: hTmetersh_T \, \text{meters}
  • Tree's shadow length: sT=31.35meterss_T = 31.35 \, \text{meters}

From the problem, we know the total shadow length is 31.35 meters. Dalvin is standing 27.2 meters from the tree, so the length of Dalvin's shadow is: sD=31.3527.2=4.15meterss_D = 31.35 - 27.2 = 4.15 \, \text{meters}

Now, we can use the property of similar triangles: the ratios of corresponding sides are equal. This gives us the proportion: hDsD=hTsT\frac{h_D}{s_D} = \frac{h_T}{s_T} Substitute the known values: 1.854.15=hT31.35\frac{1.85}{4.15} = \frac{h_T}{31.35} Now, solve for hTh_T (the height of the tree): hT=1.85×31.354.15h_T = \frac{1.85 \times 31.35}{4.15}

Let me calculate that.The height of the tree is approximately 13.98meters13.98 \, \text{meters} to the nearest hundredth.

Would you like more details on how this was calculated or have any other questions?

Here are 5 related questions to deepen your understanding:

  1. How would the height of the tree change if Dalvin was closer to the tree?
  2. What if the length of the tree's shadow was shorter, how would that affect the tree's height?
  3. How does the concept of similar triangles help in real-world applications like this one?
  4. Can you use this method to find the height of an object if the shadows are not aligned?
  5. What other methods could be used to find the height of a tall object using shadows?

Tip: Whenever dealing with proportions in geometry, make sure to carefully match corresponding sides or angles to avoid calculation errors!

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Math Problem Analysis

Mathematical Concepts

Similar Triangles
Proportions
Geometry

Formulas

h_D / s_D = h_T / s_T

Theorems

Similar Triangle Theorem

Suitable Grade Level

Grades 8-10