Math Tips
Written by Lisa Salzman
Back in the day, I was one of those students who liked math class. Call me crazy, but I liked the process and sequential steps of working out a problem. Today I have 5 kids and I find that some of them “get” math and others, not as much.
In the early days of NICET, they had Basic Math and Intermediate Math work elements. These two elements were required for various levels and subfield certifications. Math can be fun! Let’s review a couple of basic exercises on Area and Volume.
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- Area is a two-dimensional measurement of the surface inside a plane (flat) geometric figure.
- Volume is the amount of space occupied by a three-dimensional object, such as a box or tank.
Area and volume have different units of measurement that should never be mixed. Once you have picked a unit, you must convert all other units to the chosen unit. The following is a table which shows the two different types of units.
Area of a Rectangle:
Problem: Determine the area of a room having sides measuring 20 ft and 15 ft.
Solution: The area (A) of a rectangle is length times width (L x W).
Our length (L) = 20 feet and our width (W) = 15 feet.
A = L x W Substitute length and width values
A = 20 ft x 15 ft Multiply
A = 300 ft.²
Note the units: Multiplying feet by feet = square feet (ft.²).
Remember, if this were a square room rather than a rectangular room, the formula for area would be the same (L * W).
Volume of a Rectangle
Suppose you need to find the volume of a rectangular tank, where the length is 200 ft, the width is 10 ft, and the depth is 12 ft.
Exercise #2: Find the volume of the tank shown below.
The volume (V) is determined by taking our cross-sectional area, which is the area of the bottom of the tank, and multiplying it by the depth (D) of the tank. In this case, the depth is 12 ft.
Solution #2: The formula for calculating volume is:
Volume = Area x Depth (or Volume = Length x Width x Depth)
V = L x W x D written in formula format
Our variables are:
- Length = 200 ft.
- Width = 10 ft.
- Depth = 12 ft.
Substituting the given values into the formula gives:
V = 200 ft x 10 ft x 12 ft
V = 24,000 cubic feet or 24,000 ft.³
NOTE: Remember to watch your units and remember that feet x feet x feet equals cubic feet, or ft.³.