Which of the following statements is true? A. Point, line, and plane are undefined terms. B. A theorem is an accepted statement of fact. C. "Vertical angles are congruent" is a definition. D. A postulate is a conjecture that is proven.

Step 1: Define the Problem

Identify the key components of the question that need to be addressed: Determine which statement among the given options is true.

Step 2: Break Down the Problem

Divide the problem into smaller, manageable parts:

• Analyze each statement individually to determine its truthfulness.

Step 3: Apply Relevant Concepts

Use appropriate academic theories or formulas to solve each part of the problem:

• Statement A: Point, line, and plane are considered undefined terms in geometry because they are the basic building blocks used to define other terms.
• Statement B: A theorem is not an accepted statement of fact; it is a statement that has been proven based on previously established statements, such as other theorems, and axioms.
• Statement C: "Vertical angles are congruent" is not a definition; it is a theorem that can be proven using the properties of angles.
• Statement D: A postulate is not a conjecture that is proven; it is an accepted statement or assumption used as a basis for reasoning or argument without proof.

Step 4: Analysis, Verify and Summarize

Analyze each part in detail if necessary, verify the calculations result, and summarize the findings:

• Statement A is true because point, line, and plane are indeed undefined terms in geometry.
• Statement B is false because a theorem requires proof.
• Statement C is false because it describes a theorem, not a definition.
• Statement D is false because a postulate is accepted without proof, unlike a conjecture.

Final Answer

The true statement is: A. Point, line, and plane are undefined terms.