Midsegments of triangles

Design by Delta publications

key notes :

A midsegment of a triangle is a line segment that connects the midpoints of two sides of a triangle.
✏️ Think of it as the “middle connector”!


Parallel to the third side

  • The midsegment is always parallel to the side of the triangle that it does not touch.
  • 🟒 Example: If AB and AC are sides, and D and E are their midpoints, then DE βˆ₯ BC.

Half the length of the third side

  • The length of the midsegment = Β½ Γ— length of the side it is parallel to.
  • ✨ Formula: DE = Β½ Γ— BC

Forms a smaller triangle inside

  • Two midsegments can form a triangle inside the original triangle, similar to the main triangle.

  • Look for points exactly halfway along two sides.
  • Connect them with a straight line.
  • Check if it is parallel to the third side and half its length.

  • Helps in finding missing lengths in triangles.
  • Used in coordinate geometry to find midpoints and slope relationships.
  • Makes triangles similar and proves congruence in parts of triangles.

  • Draw a triangle πŸ›†
  • Mark midpoints of two sides πŸ”Ή
  • Connect them πŸ”Έ
  • Notice how the midsegment forms a mini parallel line inside the triangle

  • Midsegment = connects midpoints
  • Parallel to third side βˆ₯
  • Length = Β½ of third side

Learn with an example

Let’s practice!✍️