Marking centroid of a triangle

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This is a hands on activity to explore concurrent lines formed in a triangle when vertices are joined to the midpoints of the opposite side.

Objectives

Introduce medians of a triangle

Estimated Time

30 minutes.

Prerequisites/Instructions, prior preparations, if any

Children should know basics of triangles

Materials/ Resources needed

Non digital: Wax paper, pencil and ruler.

Process (How to do the activity)

  1. On the piece of wax paper, use your pencil and ruler to draw a triangle.
  2. Draw different types of triangles: Acute, Obtuse, or Right angled triangle.
  3. Choose 1 side of your triangle. Fold your paper so that the endpoints of the side you’ve chosen are overlapping. Make a very small crease through the side of the triangle. This is the midpoint of the side.
  4. Fold a crease in the triangle from this midpoint to the opposite vertex. You have now constructed the MEDIAN of one side of the triangle.
  5. Use the same process to construct a median for the other two sides of the triangle.
  6. What do you notice about their intersection point? The intersection point is called the centroid.
  • Developmental Questions:
  1. Where does the median lie in case of acute, obtuse and right triangles ?
  2. Identify the centroid.
  3. Into how many parts does the centriod divide the median ?
  4. Compare your triangle and results to your partners.
  5. Is centriod exactly in the middle of the median ?
  • Evaluation:
  1. Where exactly does the centroid lie on each median ?
  • Question Corner
  1. What is the position of the centroid in different types of triangles?