If a line is not parallel, the sides are always divided proportionally.

If AD/DB = AE/EC, what can we conclude? A) DE ⟂ BC B) DE ∥ BC C) DE = BC D) Triangle ABC is isosceles

The Theorem is called the Basic Proportionality Theorem.

In △ABC, if DE ∥ BC, then which of the following is true? A) AD = DB B) AE + EC = AD + DB C) AD/DB = AE/EC D) AD × DB = AE × EC

The theorem helps prove which geometric property? A) Area of triangles B) Proportional sides C) Congruence of triangles D) Perimeter of polygons

If a line is parallel to one side of a triangle, it divides the other two sides: A) Equally B) Perpendicularly C) Proportionally D) Unequally

The Triangle Proportionality Theorem only applies when: A) The line passes through the midpoint of one side B) The line is parallel to one side C) The triangle is right-angled D) All sides are equal

In a triangle, if a line divides the sides proportionally, it must be: A) Perpendicular to the base B) Parallel to the base C) Tangent to the base D) None of these

The converse of the theorem proves a line is parallel if the sides are divided proportionally.

The theorem works for any triangle shape (scalene, isosceles, or equilateral).