Question

State which postulate, definition, or theorem justifies the statement about the diagram.

$BD+DC=BC$

Short answer

The Midpoint Theorem justifies the statement about the diagram.

Step-by-step solution

Step 1. Observe the given diagram.

The diagram constitutes a triangle ABC.

Step 2. State the Midpoint Theorem.

The theorem states that the line segment created by joining the midpoints of the triangle’s two sides is parallel and also half the length of the third side of the triangle.

Step 3. State the conclusion.

Considering the given diagram and the statement “$BD+DC=BC$”.

Therefore, the statement about the diagram is justified by the Midpoint Theorem.