11.3 Polygons

See table (Text)

Def. Curve—lies in a plane and is connected (it can be drawn without lifting a pencil).

Def. Closed curve—can be drawn with the starting and stopping points the same.

Def. Simple curve—lines do not cross themselves and only two extensions from a single point.

Def. Polygonal curve—consists of all line segments.

Def. Polygon—closed, simple, polygonal curves.

Def. Convex curves—closed, simple and have no indentations.

Def. Concave curves—closed, simple, and not convex.

 Polygons Number of Sides or Vertices Triangle 3 Quadrilateral 4 Pentagon 5 Hexagon 6 Heptagon 7 Octagon 8 Nonagon 9 Decagon 10 n-gon n

Def. Interior angle of a polygon—any two sides of a polygon having a common vertex.

Def. Exterior angle of a convex polygon—determined by a side of the polygon and the extension of a contiguous side of the polygon.

Def. Congruent parts—parts that are of the same size and shape.

Def. Regular Polygons—polygons in which all interior angles are congruent and all sides are congruent.

Definitions of terms:

1. Right triangle—a triangle containing one right angle.
2. Acute triangle—a triangle in which all angles are acute.
3. Obtuse triangle—a triangle containing one obtuse angle.
4. Scalene triangle—a triangle with no congruent sides.
5. Isosceles triangle—a triangle with at least two congruent sides.
6. Equilateral triangle—a triangle with three congruent sides.
7. Trapezoid—a quadrilateral with exactly one pair of parallel sides (this is different than the text)
8. Kite—a quadrilateral with at least two distinct pairs of consecutive sides.
9. Isosceles trapezoid—a trapezoid with one pair of congruent base angles.
10. Parallelogram—a quadrilateral in which each pair of opposite sides is parallel.
11. Rectangle—a parallelogram with a right angle.
12. Rhombus—a parallelogram with all sides congruent.
13. Square—a rectangle with all sides congruent.