Unit 22

Linear Measurement

Basic Principles of Linear Measurement

• Linear measurement is the measurement of length or distance.

• In the U.S. customary system (also called the English or household system) the units of linear measurement are inches, feet, yards, and miles.

Basic Principles of Linear Measurement

• In the metric system, the unit for linear measurement is the meter.– The metric system is frequently called the

International System of Units or simply SI.– The metric system is used in many health

care fields. It is easy to use because it is based on units of tens.

Converting MetricLinear Measurements

• Metrics are easy to convert from unit to unit because they are multiples of 10.

• Placement of a number in relation to a decimal point represents different powers of 10, so metrics can be converted by moving the decimal point in relationship to the power of 10 required.

Converting Metric and English Linear Measurements

• Metric linear measurements can be converted to approximate English linear measurements.

• The easiest way to convert between English and metric measurements is to set up a proportion.

Linear Measurement

• Example: A group of student nurses is running a 5-kilometer (km) race to raise money for the United Appeal. How many miles (mi) will they run?– Find an English-metric equivalent:

1 km = 0.621 mi

– Set up a proportion:

1 km : 0.621 mi = 5 km : X mi

Linear Measurement

– Multiply the extremes:

1 x X = 1X– Multiply the means:

0.621 x 5 = 3.105

X = 3.105– The students will run 3.105 mi in the 5-km

race.

Practical Problem

• A patient is 1.8288 m in height.

• What is his height in feet?

Practical Problem

• Set up the proportion and cross-multiply:

• The patient is 6 ft tall.