27/04/2009 - 9B Class

First we started by reviewing the equations to find the area of Polygons:

Area of the parallelogram:




Area of the triangle:




Area of the Rhombus:




Area of the trapezoid:





After that we corrected the homework that was on page 539 # 11-26

Subsequent to correcting the homework Mrs. Saatkamp gave us a little piece of paper that had three pictures of polygons, one hexagon (6 sides), one pentagon(5 sides), and one octagon(8 sides).
So we chose the hexagon to start with. We drew only the diagonals that pass through the center (3). So 6 equilateral triangles were formed and we chose one to work with. Than the height of this triangle we started to call apothem.

APOTHEM - If we can divide into N numbers of triangles, apothem will be the height of one of those.

Then we called the base of the triangle base, which is not only the base of teh triangle, but also a side of the polygon.

So we calculated the area of the triangle and multiplied by six (because a hexagon has six triangles inside of it) and what we got was:


In which (p) means perimeter and (a) apothem...

So this will be always the equation to find the area of any kind of regular polygons!!!

So remember always to use SOH CAH TOA to find the measure of the heights and bases, and try to practice it without a calculator, by using the SOH CAH TOA table, because it will be required in most of our quizzes and tests.