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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.
Elements of Geometry: Containing the First Six Books of Euclid, with a ... - Page 292
by Euclid, John Playfair - 1846 - 317 pages

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

Queensland. Department of Public Instruction - Education - 1897 - 446 pages
...3. 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 Geometry

George D. Pettee - Geometry, Modern - 1896 - 272 pages
...[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...

## Plane and Solid Geometry

James Howard Gore - Geometry - 1898 - 232 pages
...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 four right angles. Therefore the exterior angles alone are equal to four right angles. QED EXERCISES....

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

Euclid, Henry Sinclair Hall, Frederick Haller Stevens - Euclid's Elements - 1900 - 330 pages
...angles. I. 15, Cor. Therefore all the interior angles of the figure, together with four right angles, are equal to twice as many right angles as the figure has sides. QEI>. COROLLARY 2. If the sides of a rectilineal figure, which has no re.entrant angle, are produced...

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

Sidney Herbert Wells - Machine design - 1900 - 202 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),...

## Land Surveying and Levelling

Arthur Thomas Walmisley - Leveling - 1900 - 354 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...

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

Education - 1902 - 940 pages
...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...

## Surveying, as Practiced by Civil Engineers and Surveyors ...: Intended as a ...

John Whitelaw - Surveying - 1902 - 634 pages
...measurements before leaving the ground, as " the sum of the interior angles of any rectilinear figure is equal to twice as many right angles as the figure has sides, less four right angles." In the case of Fig. 73, as the figure is four-sided the sum of the interior...