WOLFRAM|DEMONSTRATIONS PROJECT

Angle Bisector for an Angle Subtended by a Tangent Line

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∠DAC
≈
43.09°
∠BAC
≈
43.09°
Let a circle be internally tangent to another circle at the point A. Draw a tangent line through a point C on the inner circle and let D and B be its points of intersection with the outer circle. Then AC bisects
∠
DAB.
Drag the orange point to change the figure.