Stake Out


Purpose: To apply principles of similar triangles, To improve estimation skills, To develop computation skills
Season: All
Background information: In similar triangles, the angles are the same and the sides of the triangles are in exact proportion to each other.
Materials: Meter sticks or yardsticks, paper, pencil, string (optional), calculator (optional)
Procedure:
  1. Review the difference in congruent triangles and similar triangles.
  2. Hold a meter stick or yardstick on the ground in an upright position (h) and have someone lie down at Point A and sight with his/her eye close to the ground so that the top of the stick is in line with the top of the object being measured (a tree, the dam, etc.) (C).
  3. Measure the distances AD and AB .
  4. Establish similar triangle ADE and ABC and set up this problem to determine the height of the object.

AD = AB

h H

  • You might want to collect the data at Miller Springs and then calculate height in the classroom.
  • You might want to use a string from AD and AB. Then measure the string.
Questions:
  1. How can you measure the height of a tree or building?
  2. Why does similar triangles help?

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