Try this Drag the orange dot A.
Note how the four
vertices
of the square always lie on the circle.

A square inscribed in a circle is one where all the four vertices lie on a common circle. Another way to say it is that the square is 'inscribed' in the circle. Here, inscribed means to 'draw inside'.

The diagonals of a square inscribed in a circle intersect at the center of the circle. To see this check the 'diagonals' box in the applet above. As with all squares, the diagonals bisect each other at right angles.

Another way to think of this is that every square has a circumcircle - a circle that passes through every vertex. In fact every regular polygon has a circumcircle, and so can be inscribed in that circle.

You can construct a square inscribed in a circle using compasses and a straightedge. For more see Constructing an inscribed square.

- Polygon general definition
- Quadrilateral
- Regular polygon
- Irregular polygon
- Convex polygons
- Concave polygons
- Polygon diagonals
- Polygon triangles
- Apothem of a regular polygon
- Polygon center
- Radius of a regular polygon
- Incircle of a regular polygon
- Incenter of a regular polygon
- Circumcircle of a polygon
- Parallelogram inscribed in a quadrilateral

- Square
- Diagonals of a square
- Rectangle
- Diagonals of a rectangle
- Golden rectangle
- Parallelogram
- Rhombus
- Trapezoid
- Trapezoid median
- Kite
- Inscribed (cyclic) quadrilateral

- Regular polygon area
- Irregular polygon area
- Rhombus area
- Kite area
- Rectangle area
- Area of a square
- Trapezoid area
- Parallelogram area

- Perimeter of a polygon (regular and irregular)
- Perimeter of a triangle
- Perimeter of a rectangle
- Perimeter of a square
- Perimeter of a parallelogram
- Perimeter of a rhombus
- Perimeter of a trapezoid
- Perimeter of a kite

- Exterior angles of a polygon
- Interior angles of a polygon
- Relationship of interior/exterior angles
- Polygon central angle

- Tetragon, 4 sides
- Pentagon, 5 sides
- Hexagon, 6 sides
- Heptagon, 7 sides
- Octagon, 8 sides
- Nonagon Enneagon, 9 sides
- Decagon, 10 sides
- Undecagon, 11 sides
- Dodecagon, 12 sides

(C) 2011 Copyright Math Open Reference.

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All rights reserved