Circle Relationship Formulas

2 Tangents Segment Relationship

• Length of Tangent #1 = Length of Tangent #2

• Length of Tangent #1 > Length of Tangent #2

• Length of Tangent #1 < Length of Tangent #2

• Length of Tangent #1 + Length of Tangent #2 = 0

Central Angle - Arc Measure Relationship

• Central Angle Measure = Intercepted Arc Measure

• Central Angle Measure = Half of Intercepted Arc Measure

• Central Angle Measure = Twice the Intercepted Arc Measure

• Central Angle Measure = Sum of Intercepted Arc Measures

Arc Length

• Length of the Pizza Crust

• Total Length of the Circle

• Diameter of the Circle

• Radius of the Circle

Inscribed Angle - Arc Measure Relationship

• Angle = 1/2 Intercepted Arc

• Angle = Intercepted Arc

• Angle = 2 x Intercepted Arc

• Angle = Intercepted Arc / 2

Circumference of a Circle

• C = Pi x Diameter

• C = 2 x Pi x R

• C = Pi x Radius

• C = Diameter x Radius

Inscribed Angle (Chord/Tangent) - Intercepted Arc Relationship

• Angle = 1/2 Intercepted Arc

• Angle = Intercepted Arc

• Angle = 2 x Intercepted Arc

• Angle = Intercepted Arc / 2

Vertex Outside The Circle Arc-Angle Relationship

• Angle = 1/2(Large Arc - Small Arc)

• Angle = 1/2(Large Arc + Small Arc)

• Angle = Large Arc - Small Arc

• Angle = 2(Large Arc - Small Arc)

Vertex Inside (2 Chords Intersecting)

Arc - Angle Relationship

• Angle = 1/2 (Arc #1 + Arc #2)

• Angle = Arc #1 + Arc #2

• Angle = 1/2 (Arc #1 - Arc #2)

• Angle = Arc #1 - Arc #2

Sector Area

• "Pizza Slice"

  Degree/360 x Pi x R^2

• "Circle Area"

  Pi x R^2

• "Triangle Area"

  1/2 x Base x Height

• "Rectangle Area"

  Length x Width

Secant/Tangent Segment Relationship

• Whole^2 = Outside x Whole

• Whole = Outside + Whole

• Whole^2 = Outside^2 + Whole^2

• Whole = Outside x Whole^2