14.1 Areas of Polygons and Circles


Area on a Geoboard (or dot paper)


addition method: sum the area of the figure by finding the area of the smaller parts and then adding them together




a) b)











subtraction method: Figure








Figure a) and b)


















Area of a Rectangle



Formula: A = lw












Example: Find the area of each rectangle (Figure a) and b))














Area of a Parallelogram


Formula: A = bh









Area of a Triangle


Formula: A = bh




Examples: Find the area for each (Figure)


a)      A = bh



b)      A = bh



c)      A = bh



d)     A = bh



e)      A = bh




Area of a Trapezoid




Formula: A = h (b1 + b2)



Examples: Figure



a) b)


















Area of a Regular Polygon




Formula: A = ap










Area of a Circle




Formula: A =