ch.1 Section 6 Polygons

Polygons

Today in class we learned all about polygons!! Polygons are:

• shapes that have AT LEAST three sides
• each side MUST intersect with exactly two other sides

We also learned that there are many different types of polygons. To the left is a chart that lists all the different types of polygons.



We also learned about five different types of polygons:

concave polygon- this is a polygon that if you were to extend its sides then the lines would go through he interior of the shape

convex polygon- this is a polygon that if you were to extend the sides then the lines would NOT go through the interior of the polygon.

equilateral polygon- all the sides are congruent, meaning they are all the same length

equiangular polygon- All the interior angles are congruent

regular polygon- a polygon that is both equiangular and equilateral

Another thing we learned during class was about how to find the area and perimeter of polygons and also a circle

AREA:
square - a side of the square to the second power or squared (written out on right)
rectangle- base times height

triangle: 1/2bh this means the base of the triangle times the height. To recognize where the height is make sure that it is both of these two things:

• The height is always perpendicular to the base
  
• always forms a right angle

PERIMETER:
All polygons- the sum of all the sides equals the perimeter

CIRCLE:
area- area is pi times radius squared.

• radius is half of the diameter
• pi is approx. 3.14

circumference (perimeter)- two times pi times radius