Curves by ewghwehws


									              Curves and Polygons
A curve is a set of connected points in a plane.

A simple curve can be drawn without lifting the pencil from the paper and
without passing through any point twice.

A closed curve begins and ends at the same point.

A figure is convex is it can be drawn with a simple closed curve and for any two
points A and B inside the figure AB is completely inside the figure.

A polygon is any simple closed curve made up of straight line segments.
Polygons do not need to be convex
                     Different Polygons
triangle - 3 sides               quadrilateral - 4 sides    pentagon - 5 sides

hexagon - 6 sides             heptagon - 7 sides           octagon - 8 sides

 A nonagon has 9 sides and a decagon has 10 sides
Classify by angle:

                            Obtuse triangle              Right triangle
Acute triangle
                            One angle is > 900           One angle = 900
all angles are < 900

Classify by sides:

Equilateral triangle             Isosceles triangle    Scalene triangle
All three sides are equal        two sides are equal   no sides are equal
   Exterior Angles of a Triangle

                         1                       3      6

The measure of an exterior angle of a triangle is equal to the sum of the measures
of the two opposite interior angles.
Classify by sides:

Trapezoid               Parallelogram                 Rhombus
two sides parallel      opposite sides parallel       parallelogram with all
                        opposite sides equal          4 sides equal

Classify by angles:

    Rectangle                                     Square
    parallelogram with one right angle            rectangle with 4 equal sides
    (therefore all 4 angles equal 900)            or rhombus with right angles
A circle is the set of points in a plane all the same distance from a given point (called the

O - center
OQ - radius

PR - diameter
PQ - chord                                                         O

PQ - secant                                                                     T

RT - tangent

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