Theorems baiiii

• Theorem 2.1 - The line at any point of a circle is perpendicular to the radius of the circle at the point of Tangency.

  
• Theorem 2.2 - The lengths of two tangents drawn from an external point to a circle are equal.

  
• Theorem 2.3 - The measure of an angle formed by a tangent and a chord intersecting at the point of tangency is half the measure of the intercepted arc.

  
• Theorem 2.5 - In a circle, when a secant segment and a tangent segment are drawn from the same point in the exterior, the product of the lengths of the secant segment and its external part equals the square of the length of the tangent segment.

  
• Theorem 2.4 - The measure of an angle formed by two secants, two tangents, or a secant and a tangent intersecting in the exterior of a circle is half the positive difference of the measures of the intercepted arcs.

  
• Theorem 2.6 - In a circle, when a secant segment and a tangent segment are drawn from the same point in the exterior, the product of the lengths of the secant segment and its external part equals the square of the length of the tangent segment.