# 4: Triangles

- Page ID
- 442

- 4.4: Isosceles Triangles
- Properties of triangles with two equal sides/angles.

- 4.23: Medians
- Line segment that joins a vertex and the midpoint of the opposite side of a triangle.

- 4.36: Distance and Triangle Classification Using the Pythagorean Theorem
- Find missing sides to calculate the area.

Thumbnail: Diagram of two congruent triangles. \(\triangle\ ABC \cong\ \triangle\ DEF\) (CC BY-SA; Merovingian via Wikipedia)