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The area of a polygon is the number of square units that the figure covers. Area is measured in square units, such as square feet or square miles. An example is the area of a square whose sides each measure 2 inches long -- the area is 2*2=4 square inches.
Area of a Rectangle
The area of a rectangle is the product of its length and width: A = lw
Area of a Triangle
The area of a triangle is half the area of a rectangle -- half the product of a base and its corresponding height: A = (1/2) bh
Area of a Parallelogram
A parallelogram is a quadrilateral with two pairs of opposite sides that are parallel to each other. Any side of a parallelogram can be called a base. Each base has a corresponding altitude, and the length of the altitude is the height of the parallelogram.
The area of a parallelogram is equal to the area of a rectangle with the same base and height as the parallelogram -- the area of a parallelogram is the product of a base and its corresponding height: A = bh
Area of a Regular Polygon
In a regular polygon, all sides are congruent and all angles are congruent. You can find the area of the regular polygon if you know the length of one side of the polygon and the length of the apothem. The apothem is the perpendicular segment from the center of a regular polygon to one of its sides -- the length of the apothem is the height of the triangle formed by a side and the two segments from the center to the endpoints of this side. The area of a regular polygon is half the product of the apothem (a) and the perimeter (P): A = (1/2) a*P
Another way to look at the formula for area of a regular polygon is to find the area of
one the triangles found in the polygon and multiplying by the number of sides in the polygon: A = (1/2) bh * n, where h is the height of the triangle (the apothem of the polygon), b is the length of one side of the polygon and n is the number of sides of the polygon.
This video shows you how to find the area of a regular hexagon if...
This video shows you how to find the area of a regular hexagon if you're given a radical in the side length.
Area of a Quadrilateral with Perpendicular Diagonals
To find the area of a quadrilateral that has perpendicular diagonals (such as rhombus, square, and kite), find the half the product of the diagonals: A = (1/2) d1*d2
 
Area of a Trapezoid
The area of a trapezoid is half the product of the height and the sum of the bases: A = (1/2) h*(b1 + b1)
This video shows you how to find the area of a circumscribed...
This video shows you how to find the area of a circumscribed trapezoid.
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Perimeter, Circumference, and Area
