A fine though circumscribed group of buildings is that in the heart of the City which includes the Bank of England, the Royal Exchange and the Mansion House.
The determination of the side of a regular heptagon which can be inscribed or circumscribed to a given circle was reduced to a more complicated equation which was first successfully resolved by Abul Gud.
The land thus circumscribed extends between the parallels of 46° 40' and 36° 38' N., and between 6° 30' and 18° 30' E.
The most notable of these fall within a circumscribed area, and it is therefore necessary to preface their consideration with a statement of the broader characteristic divisions of the metropolis.
The fourth book deals with the circle in its relations to inscribed and circumscribed triangles, quadrilaterals and regular polygons.