Chapter 9-3: Polygons
Polygon - closed figure with at least 3 sides- no curves - no overlapping lines
Named by the number of sides (called laterals) or their number of angles
Polygon literally means MANY (poly) ANGLES (gon)
Triangles - literally means 3 angles (and sides) - Each has 2 names
By angles: Acute, Obtuse, Right
By sides: Scalene, Isosceles, Equilateral
Triangles have 180 degrees
Quadrilaterals - literally means 4 laterals (sides) and angles - 360 degrees (2 triangles!)
Trapezoids - Only 1 set of parallel lines
Kite - no parallel lines - 2 adjacent sides are congruent
Parallelogram - Oppositie sides parallel and congruent
Types of parallelograms:
Rhombus - all sides congruent
Rectangle - 4 right angles
Square - Rectangle with all sides congruent (so it's also a rhombus)
A square is a regular rectangle
Regular polygons - all sides and angles congruent
2 famous ones - equilateral triangle and squares
ALL REGULAR POLYGONS ARE SIMILAR!
So to find the PERIMETER of a regular figure, you just need to know one side and multiply by the total number of sides.
Chapter 9-5: Congruent polygons
If two polygons are congruent, they all their corresponding parts are congruent
We use tick marks to denote congruent sides and angles.
There are 3 ways to show that triangles are congruent:
SSS = side, side, side = all corresponding sides are congruent
SAS = side, angle, side = 2 sides with the angle that is between them
ASA = angle, side, angle = 2 angles with the side between them
THERE IS NO SUCH THIS AS ASS OR AAA!!!!!!!!
If all angles are congruent, then they may be congruent or SIMILAR
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