Unit of Length

Even before the idea of measurements got consistent it was largely driven by who was doing the measuring. A yard was the distance from the tip of the nose to the end of an outstretched arm or foot. An inch was considered often as the length of the index finger’s second bone.

The units of measure for length most commonly used in the United States are inches, feet, yards and miles. Units of measurement are not case sensitive and so we could use either "CM" or "cm" to set a measure for a given rule when we are using centimeters.

Inches are standard measure of length in the imperial system of measurement.
The measure for converting mm to inch would be, 25.4 mm to an inch, 10 mm to cm and 2.54 cm to inch.

Pica’s and points are basic typesetting units of measure. There are 72 points for an inch, 12 points for 1 pica, and 6 pica’s equals to1 inch. The p-length and q-height refer to the length and height of the letters’ ‘p’ and ‘q’ respectively, while Pixels are the standard units of measure for gauging the height and width on computer screens.

Some equivalent measures are 12 inches = 1foot, 3 feet = 1 yard, 5280 feet = 1 mile. 

Conversion of Lengths:

·         Feet to inches: number of inches = number of feet x 12 ·         Inches to feet: number of feet = number of inches ÷ 12 ·         Yards to feet: number of feet = number of yards x 3 ·         Miles to feet: number of feet = number of miles x 5,280

To make length easy to remember, this method will help : 

Example of length conversion :

a) Suppose we need to buy one fabric of 3 feet and the store we intend to buy from is selling that in meters,      then we need to think quickly and convert the required length of fabric from feet into meters.

  Solution:

   Here, one meter is equivalent to 3.28 feet or 3 feet is equivalent to 0.3048 meters. 

   So we have to buy 3 times this converting factor. So, fabric bought would be equivalent to 

    (3 x 0.3048) m 

    = 0.9144 meters

b) 6 Km = ? m

    Solution:

    Need to x 1000

    6 x 1000 = 6000 m

c) 130 cm = ? m

    Solution:

    Need to ÷ 100

    130 ÷ 100 = 1.3 m

Exercise:

a) 51 cm (mm)                                       d) 45.5 mm (cm)  

b) 23 m ( cm)                                         e) 0.0039 km (cm)

c) 120 m (mm)

                

Solution :

a) 51cm x 10                                           d) 45.5 mm ÷ 10

    = 510 mm                                                = 4.55 cm

b) 23 m  x 100                                        e) 0.0039 km x 1000 x 100

= 2300 cm                                                  = 390 cm

c) 120 m x 100 x 10

= 120,000 mm