...by more than four straight lines, as ABODE. 39. A POLYGON of five sides is called a Pentagon ; one of six sides, a Hexagon ; of seven sides, a Heptagon;...of nine sides, a Nonagon ; of ten sides, a Decagon, &c. I PROBLEMS. PEOB. I. To draw a straight line parallel to AB, and as far from it as the point C...

...distinguished according to the number of their sides ; thus a figure of five equal sides is termed a pentagon, of six sides a hexagon, of seven sides...octagon, of nine sides a nonagon, of ten sides a decagon, of eleven sides an uudecagon, and of twelve sides a dodecagon. TO FIND THE AREA OF A POLYGON. Multiply...

...polygons ; and receive other particular names, according to the number of their sides : thus, a figure of five sides is called a pentagon ; of six sides - a hexagon; of seven - a heptagon ; of eight - an octagon ; of nine - a nonagon ; of ten - a decagon ; of eleven - an undecagon...

...polygon, that of three sides, is called a triangle ;% that of four sides, a quadrilateral; of five sides, a pentagon; of six sides, a hexagon; of seven sides, a heptagon; of eight sides, an octagon; of nine, a nonagon ; of ten, a decagon ; of eleven, an undecagon ; and of twelve, a dodecagon. There are four...

...B more than four straight lines, as ABODE. D 39. A POLYGON of five sides is called a Pentagon ; one of six sides, a Hexagon; of seven sides, a Heptagon;...of nine sides, a Nonagon; of ten sides, a Decagon, &c. 40. A REGULAR POLYGON is that which has all its sides and all its angles equal, as ABCDEP. CD 41....

...these terms are generally restricted to the equilateral triangle and the square. A polygon of Jive sides, is called a pentagon; of six sides, a hexagon; of seven sides, a hoptagon ; of eight sides, an octagon ; &c. A polygon of ten sides is called а decagon; of twelve...

...Sit. VII.— OF POLYGONS IN GENERAL. DEFINITIONS. 1. A polygon of five sides is called a PENTAGON; one of six sides, a HEXAGON ; of seven sides, a HEPTAGON ; of eight sides, an OCTAGON ; of ten sides, a DECAGON ; of twelve sides, a DODECAGON. 2. A regular polygon is one which is both equilateral...

...called a POLYGON. Polygons receive particular names from the number of their sides and angles ; thus a polygon of five sides is called a PENTAGON ; of six...seven sides, a HEPTAGON ; of eight sides, an OCTAGON, etc. 32. The ALTITUDE of a triangle or parallelogram is the perpendicular drawn from the opposite angle...

...eight sides. An octagon is a figure of eight sides. A figure of four sides is called a square. A figure of five sides is called a pentagon, of six sides a hexagon, of eight sides an octagon. There might be a figure of seven sides, but it would not be very easily made,...

...angles. A polygon of three sides is called a Triangle, of four sides a Quadrilateral, of five sides a Pentagon, of six sides a Hexagon, of seven sides a Heptagon, of eight sides an Octagon, etc. 409. Mensuration treats of the measurement of lines, planes, and solids or volumes (Art. 199)....