Construction Estimating Formulas & Useful Information

2.  The area of a rectangle is equal to its base x height. (A = b x h).

  

For example:     10 x 5 = 50

3.  The area of a square is equal to its base x height (see above).
               -or-
  The area of a square is equal to the square of one of its sides. (A = S squared). 

For example:     5²=25

4.  The area of a triangle is equal to 1/2 the product of its base and height. A = 1/2 (b x h).

For example:     10 x 10 = 100 x 1/2 = 50

5.  Circles

The area of a circle is equal to 1/2 the product of its radius and circumference. (A = 1/2 (r x c).  

For example:            radius = 5, circumference = 31.42:   5 x 31.42 = 157.1 x 1/2 = 78.55

 -or-

                                A=π r², 3.1416(5 x 5) = 3.1416 x 25 = 78.54

-or-

A= d² x .7854

Find the circumference of a circle by multiplying the diameter x (π).  Find the volume of a cylinder by multiplying the height x the area of the circle.

*π = 3.1416