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1.30 Construct a Centroid

The point where a triangle's three medians intersect is called the centroid. A median of a triangle is a segment connecting a vertex to the midpoint of its opposite side. To construct the centroid, it is sufficient to find the intersection of two medians, since the third median will also pass through this point. Construct a Centroid using MIDPOINT Toolbar Image tool Follow the steps below to construct the centroid.
  1. Construct the midpoint of side AB. Click on Toolbar Image and then on A and B. *Repeat this step with side AC.
  2. Construct a median on segment AB: Click on Toolbar Image to connect the midpoint of AB with point C.
  3. Construct a median on segment AC. Click on Toolbar Image to connect the midpoint of AC with point B.
  4. Mark the centroid (the point of intersection of the medians): Click on Toolbar Image and then click on each median.
Construct a Centroid using COMPASS Toolbar Image tool 1) Construct the midpoint of side AB.
  • Construct a circle with radius AB centered on A. Click on Toolbar Image and then on point A and point B. Then, click on point A again to center on point A.
  • Construct a circle with radius AB centered on B. Click on Toolbar Image and then on point A and point B. Then, click on point B again to center on point B.
  • Mark the points of intersection of the two circles. Click on Toolbar Image and then click on each circle.
  • Construct a segment (perpendicular bisector) between the two points of intersection of the circles. Click on Toolbar Image and then click on the two points of intersection.
  • Construct the midpoint of side AB. Click on Toolbar Image and then click on the perpendicular bisector segment and then click on side AB of the triangle.
  • Hide the circles, segment, and points of intersection of the circles. Click on Toolbar Image and then on any part that you want to hide. *Be sure not to hide the original triangle or the midpoints of the sides of the triangles.
  • Repeat these steps with side AC.
2) Construct a median on segment AB: Click on Toolbar Image to connect the midpoint of AB with point C. 3) Construct a median on segment AC. Click on Toolbar Image to connect the midpoint of AC with point B. 4) Mark the centroid (the point of intersection of the medians): Click on Toolbar Image and then click on each median.