A rectilinear figure is said to be inscribed in a rectilinear figure when the respective angles of the inscribed figure lie on the respective sides of that in which it is inscribed.
Definition 2
Similarly a figure is said to be circumscribed about a figure when the respective sides of the circumscribed figure pass through the respective angles of that about which it is circumscribed.
A circle is said to be circumscribed about a figure when the circumference of the circle passes through each angle of the figure about which it is circumscribed.
Definitions 1 and 2: The first figure shows a smaller quadrilateral inscribed in a larger quadrilateral, and the larger one is circumscribed about the smaller one.
Definitions 3 and 6: The second figure shows a quadrilateral inscribed in a circle, and the circle is circumscribed about the quadrilateral.
Definitions 4 and 5: The third figure shows a circle inscribed in a quadrilateral, and the quadrilateral is circumscribed about the circle.
Definition 7: In the second figure, each side of the quadrilateral is fitted into the circle.
