Math Tools for Journalists – Analysis of Chapters 9-12

By Kellye Coleman

Directional Measurements

Time, rate and distance

An ability to calculate directional measurements such as time, rate, speed and distance is an important tool for journalists to have. It may be tempting to simply print numbers offered by people in the story, but to ensure accuracy, journalists must have the skills to calculate these figures.

Problems focused on time, rate and distance have a three-part formula that can be used regardless of which of the three elements one needs to calculate. The key is keeping the unit of measurements the same. For example, if the time is in hours, the rate must be in miles per hour and the distance in miles.

Formulas –

(the elements are switched around, depending on which elements one is calculating)

Speed and Momentum

Speed vs. Velocity

Speed = measures how fast something is going;velocity = indicates how fast something is going and the direction it’s going in

Average speed is simply another word for rate, so it can be calculated using the rate formula:

Average speed = distance ÷ time

Momentum, a combination of mass and velocity, is the force that is necessary to stop an object from moving.

Momentum = mass x velocity

 Area Measurements

Not only is it important to know how to calculate measurements, but journalists also must express measurements clearly. This expression can occur in two ways:

1)    Analogies help readers visualize the size of something as it relates to another thing. Example: “The hail was the size of a golf ball.”

2)    Numbers are sometimes essential, particularly when the size of something could directly impact readers

Perimeter, the boundary or distance around a particular object or area, is often used when writing about construction projects or housing developments. If an object or area is a square or a rectangle, calculate perimeter using this formula:

Perimeter = (2 x length) + (2 x width)

Area, the part of an object or surface, is important to know, particularly when dealing with square and rectangle objects or structures. Area is used in a variety of stories, from features to technical, and can be calculated easily.

Area (of square/rectangle) = length x width

Volume Measurements

“Volume measurements play a key role in many articles. How many tons of rock salt does a town need to handle a rough winter? How much salt is needed per mile of road? How much salt can each truck hold?” – Math Tools for Journalists

Liquid measurements

Rectangular Solid

Volume = length x width x height

The Metric System

The metric system is used in many areas worldwide, and it is important for journalists, particularly those writing about international commerce, to understand how it works.

In order to convert American lengths to metric, there are several formulas on can use:


–       inches by 25.4 to find millimeters or 2.5 to find centimeters

–       feet by 30 to find centimeters or 0.3 to find meters

–       yards by 90 to find centimeters or 0.9 to find meters

–       miles by 1.6 to find kilometers

Follow these formulas to convert metric lengths to American lengths:


–       millimeters by 0.04 to get inches

–       centimeters by 0.4 to get inches

–       centimeters by 0.033 to get feet

–       meters by 39 to get inces

–       meters by 3.3 to get feet

–       meters by 1.1 to get yards

–       kilometers by 0.62 to get miles


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