# Marking centroid of a triangle

From Karnataka Open Educational Resources

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.

## Contents

### 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)

- On the piece of wax paper, use your pencil and ruler to draw a triangle.
- Draw different types of triangles: Acute, Obtuse, or Right angled triangle.
- 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.
- 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.
- Use the same process to construct a median for the other two sides of the triangle.
- What do you notice about their intersection point? The intersection point is called the centroid.

- Developmental Questions:

- Where does the median lie in case of acute, obtuse and right triangles ?
- Identify the centroid.
- Into how many parts does the centriod divide the median ?
- Compare your triangle and results to your partners.
- Is centriod exactly in the middle of the median ?

- Evaluation:

- Where exactly does the centroid lie on each median ?

- Question Corner

- What is the position of the centroid in different types of triangles?