Geometry · Triangles & Congruence

Midsegment

HSG-CO.C.10

Definition

A segment joining the midpoints of two sides of a triangle, parallel to the third side and half its length.

Examples

  • A midsegment is half the length of the base it's parallel to.
  • If the base of a triangle is 10 units, its midsegment is 5 units.

Key rule

A midsegment is always parallel to the third side and exactly half its length.

Memory hook

Half the length, parallel to the far side.