Page 1: Core Circle Theorems and Properties

This page presents the fundamental circle theorems and properties essential for geometric analysis. The theorems are presented visually with clear diagrams for better understanding.

Definition: A cyclic quadrilateral is a four-sided figure whose vertices all lie on a circle's circumference.

Highlight: The angle in a semi-circle is always 90 degrees, forming a right angle.

Key theorems covered include:

• The relationship between angles at the center and circumference
• Properties of tangents and radii
• The alternate segment theorem
• Equal angles from the same arc

Example: When two tangents are drawn from an external point to a circle, these tangents are always equal in length.

Vocabulary: Circumference - the boundary or perimeter of a circle Vocabulary: Radius - a straight line from the center of a circle to its circumference