Some of you might find this useful in the future.
Area Measurements
Measuring and calculating area takes two of the three dimensions into
account: width
and length, as when measuring a floor, or width and height, as when
measuring a wall.
For the following examples, we'll use a rectangular room that is 10' wide
and 12'
long and has 8' high ceilings.
Area of the floor or ceiling: To figure the area of the room, multiply the
length
by the width (10' x 12' = 120 square feet).
Area of the walls: The area of each wall would either be 80 square feet (10
x 8 =
80) or 96 square feet (12 x 8 = 96). If you need the total square footage of
the
walls - for figuring paint or wallpaper for example - you can simplify the
calculation
by adding all the wall lengths together first, then multiplying by the
height (10
+ 12 + 10 + 12 = 44 x 8 = 352 square feet of total wall area).
Area in square yards: There are a total of 9 square feet in a square yard,
so to
calculate the number of square yards in this room, as when ordering carpet,
divide
the total square footage of the floor by 9 (120 square feet / 9 = 13.33
square yards).
Area in square inches: There are 144 square inches in a square foot, so to
convert
an area from square feet into square inches, simply multiply by 144 (120
square feet
x 144 = 17,280 square inches).
Area of a triangle: For the area of a triangle, use this formula: .5 x the
base of
the triangle x the height of the triangle. If you have a triangle - a gable
end for
example - that is 18 feet wide at the base and six feet high from the base
to the
peak, the calculation would be as follows (.5 x 18 x 6 = 54 square feet).
Area of a circle: To calculate the area of a circle, the formula is: pi x
radius
2
(pi = 3.1416). So, if you want to know the area of a circle with a 22-foot
diameter
- which would be an 11-foot radius - the calculation would be: (3.1416 x 11
x 11
= 380.13 square feet).
Circumference of a circle: To calculate the circumference of the same
circle - the
total distance around it - use the formula: pi x diameter: (3.1416 x 22 =
69.12 feet).
Cubic Measurements
Cubic measurements take all three dimensions into consideration - width,
length and
height. This will tell you the volume of a given area and is useful for such
things
as knowing how much air is in a room when sizing an exhaust fan or the
volume of
a foundation form when ordering concrete.
Volume of a room: To calculate the number of cubic feet in the room used in
the examples
above, multiply the width by the length by the height: (10' x 12' x 8' = 960
cubic
feet).
Volume in cubic feet: There are 27 cubic feet in a cubic yard. So, if you
would like
to convert cubic feet into cubic yards, which is used for such things as
dirt, gravel
and concrete, just divide the number of cubic feet by 27 to arrive at the
number
of cubic yards. For example, if you have a form that is 2' wide, 10' long,
and 1
1/2' high, first figure the cubic feet, then convert to cubic yards: (2' x
10' x
1.5' = 30 cubic feet / 27 = 1.11 cubic yards).
Volume in cubic inches: There are 1,728 cubic inches in a cubic foot. To
convert
the cubic feet in the above example into cubic inches, you would multiply by
1,728
(30 cubic feet x 1,728 = 51,840 cubic inches).
Board Feet
Most lumber is sold by the board foot, which is equal to a board that is one
foot
long, one foot wide, and one inch thick. If you would like to know how many
board
feet are in a given piece of lumber, use the following formula:
T x W x L / 12, where T = the thickness of the board in inches, W = the
width of
the board in inches, and L = the length of the board in feet.
For example, suppose you would like to know how many board feet are in a 16
foot
long piece of 2 x 8 lumber. Applying the above formula, you would have the
following:
2 x 8 x 16 / 12 = 21.33, so there are 21.33 board feet in that particular
piece of
lumber.
