# Dynamic Geometry Problem 1466: Tangential Quadrilateral, Newton Line, Incenter,
Midpoint, Diagonal, Collinear Points.

Let ABCD be a tangential quadrilateral and O be the center of the
inscribed circle (see the figure below). if M and N are the midpoints of
the diagonals AC and BD, prove that M, O, and N are collinear points.

See solution below

### Newton Line

Newton line is the line that connects the midpoints of the two diagonals in a quadrilateral other than a
parallelogram.

### Tangential Quadrilateral

Tangential quadrilateral or circumscribed quadrilateral is a convex quadrilateral whose sides are all tangent to a circle
inside it.

## Static Diagram of Geometry Problem 1466

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Ten problems: 1411-1420

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Quadrilateral

Tangential or Circumscribed Quadrilateral

Incenter, Inscribed circle

Circle

Circle Tangent Line

Midpoint

Collinear Points

Newton-Gauss Line

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