Circle Geometry

• Concentric Circles: Same Center, Different Radii Lengths
• Area of a Circle: πr^2
• Circumference of a Circle: πd or 2πr
• Minor Arc's Measure: Same as the central angle
• Major Arc's Measure: 360 minus the minor arc's measure
• Convert radians to degrees: radians = Radians * 180/pi
• Convert degrees to radians: Degrees * pi/180
• Vertex is outside of a circle: arc1-arc2/2
• Vertex inside the circle: arc1+arc2/2
• Vertex on circle: 1/2(intercepted arc)
• A quadrilateral inscribed in a circle has the opposite angles that add to 180 degrees.
• Chord-Chord Power Theorem: part * part = part * part
• Tangent-Secant Power Theorem: (whole)^2=part*whole
• Secant-Secant Power Theorem: part*whole=part*whole
• Equation of a circle = (x-h)^2+(y-k)^2 = r^2
• Chord-Chord Power Theorem

  
• Tangent-Secant Power Theorem

  
• Secant-Secant Power Theorem