G-C.A.2. Identify and describe relationships among inscribed angles, radii, and chords. Include the relationship between central, inscribed, and circumscribed angles; inscribed angles on a diameter are right angles; the radius of a circle is perpendicular to the tangent where the radius intersects the circle.

• Neglecting the Curvature of the Earth
• Right triangles inscribed in circles I
• Right triangles inscribed in circles II
• Tangent Lines and the Radius of a Circle