Definition:Midline of Triangle

Definition

Let $\triangle ABC$ be a triangle.

Let $D$ and $E$ be the midpoints of any two of the sides of $\triangle ABC$.

The line $DE$ is a midline of $\triangle ABC$.

Also known as

Some sources hyphenate: mid-line.

Sources

• 1968: M.N. Aref and William Wernick: Problems & Solutions in Euclidean Geometry ... (previous) ... (next): Chapter $1$: Triangles and Polygons: Theorems and Corollaries $1.26$