Geometric Proof and Reasoning

Task goals

• State a single geometric property (angle rule, triangle property, or circle theorem) as the reason for one missing angle or length in a diagram.
• Combine two or three geometric properties in a short chain of reasoning, writing each step with its own correctly named geometric reason.
• Construct a complete formal proof of a stated geometric result, such as a cyclic quadrilateral, congruent triangle, or similar triangle relationship, sequencing all statements and reasons logically and precisely.