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All the interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides.
A Course of Mathematics: For the Use of Academies as Well as Private Tuition ... - Page 292
by Charles Hutton - 1831

## Logic, Deductive and Inductive

Thomas Fowler - Logic - 1895 - 620 pages
...Generic Property. It is, for instance, a property of all rectilineal figures that the sum of their angles is equal to twice as many right angles as the figure has * F sides, minus four right angles. Thus the angles of a plane triangle are together equal to two right...

## Plane Geometry

George D. Pettee - Geometry, Plane - 1896 - 272 pages
...3 [alt. int. A (||s)] POLYGONS PROPOSITION XXX 43 111. Theorem. The sum of the angles of a polygon is equal to twice as many right angles as the figure has sides, less four right angles. Appl. Cons. Dem. i> Prove A + B + C, etc. = (2 n — 4) rt. Draw diagonals...

## Report of the Secretary for Public Instruction ...

Queensland. Department of Public Instruction - Education - 1897 - 446 pages
...Show that all the interior angles of any rectilineal 7 figure, together with four right angles, are equal to twice as many right angles as the figure has sides. 4. Parallelograms on equal bases, and between the 18 same parallels, are equal in area. 5. The complements...

## Plane and Solid Geometry

James Howard Gore - Geometry - 1898 - 232 pages
...interior angle (by 79) is equal to two right angles. That is, the sum of the interior and exterior angles is equal to twice as many right angles as the figure has sides. But by (125) the interior angles are equal to twice as many right angles as the figure has sides, less...

## Land Surveying and Levelling

Arthur Thomas Walmisley - Leveling - 1900 - 344 pages
...of all the interior angles of any rectilineal figure, together with four right angles, are together equal to twice as many right angles as the figure has sides. In a traverse survey the number of stations should be as few as possible, and as much care should be...

## A Text-book of Euclid's Elements for the Use of Schools. Books I and II, Book 1

Henry Sinclair Hall, Frederick Haller Stevens - Euclid's Elements - 1900 - 330 pages
...COROLLARY 1. All the interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides. Let ABODE be any rectilineal figure. Take F, any point within it, and join F to each of the angular...

## Engineering Drawing and Design (A Text-book Of): Including Practical ...

Sidney Herbert Wells - Machine design - 1900 - 200 pages
...which says that " the interior angles of any straight lined figure together with four right angles are equal to twice as many right angles as the figure has sides." The most common of the regular polygons used in engineering designs are the pentagon (five-sided),...

## Report of the Committee of Council on Education in Scotland...[without Appendix]

Education - 1902 - 938 pages
...prove that LP is less than LM. 3. Prove that the sum of the interior angles of any rectilineal figure is equal to twice as many right angles as the figure has sides, diminished by four right angles. 14. ABC is an equilateral triangle in which AD is drawn perpendicular...