Polygons 4-5
A polygon is a closed figure formed by joining segments ( the sides of the polygon) at their endpoints ( the vertices of the polygon). Polygons are named for the number of sides they have.
Triangle- 3 sides
Quadrilateral- 4 sides
Pentagon- 5 sides
Hexagon- 6 sides
Octagon- 8 sides
Decagon- 10 sides
A polygon is regular if ALL of its sides are congruent and ALL of its angles are congruent.
To name the polygon we name its consecutive vertices IN ORDER.
A diagonal of a polygon is a segment joining two nonconsecutive vertices.
Look at the quadrilateral on Page 123 and notice the two segments that represent the diagonals of the quadrilateral PQRS.
Certain quadrilaterals have special names.
A parallelogram has it opposite sides parallel and congruent.
A trapezoid has just one pair of parallel sides.
Certain parallelograms also have special names
A rhombus ( rhombii plural) has all it sides congruent.
A square has congruent sides and congruent angles
A rectangle has all its angles congruent.
Thus a square is a rectangle.. but a rectangle isn't necessarily a square!!
TH\he perimeter of a figure is the distance (think fence) around it. Thus the perimeter of a polygon is the sum of the lengths of its sides.
Always label your perimeters. If the figure provides a specific measure, such as meters (m), centimeters (cm), feet (ft), inches (in.)-- make sure to use that label.
If no unit of measure is given, always include "units"
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment