Topic outline

    • Measurement of Length

      We measure small lengths in cm and mm and large lengths (i.e. distances) m and km. Standard unit of length is ‘Meter’ which is written in short as ‘m’.

      1 m length is divided into 100 equal divisions. Each division is known as centimeter and written as ‘cm’. Therefore 1 m = 100 cm

      The largest distance is measured in kilometer. 1 km length is divided into 1000 equal divisions. Each division is termed as meter. Therefore 1 km= 1000 m


      According to the length conversion charts, units of lengths and their equivalents are:

      1 kilometer (km) = 10 Hectometers (hm) = 1000 m

      1 Hectometer (hm) = 10 Decameters (dam) = 100 m

      1 Decameter (dam) = 10 Meters (m)

      1 Meter (m) = 10 Decimeters (dm) = 100 cm = 1000 mm

      1 Decimeter (dm) = 10 Centimeters (cm)

      1 Decimeter = 0.1 Meter

      1 Centimeter (cm) = 10 Millimeters (mm)

      1 Centimeter = 0.01 Meter

      1 Millimeter = 0.001 Meter

      Note:

      1 mile = 1760 yards

      1 mile = 5280 feet

      1 yard = 3 feet

      1 foot = 12 inches



      An easy way to remember the above conversion chart is the following statement:


       

      Conversion

      While converting from a larger unit to a smaller unit, we multiply

      Example 1:   

      km m

      1 km = 1000 m

      Therefore, 5 km = 5 x 1000 = 5000 m

       

      Example 2:  

      m cm

      1 m = 100 cm

      Therefore, 4 m = 4 x 100 = 400 cm

       

      Example 3:   

      hm dm

      1 hm = 1000 dm

      Therefore, 20 hm = 20 x 1000 = 20000 dm



      While converting from a smaller unit to a larger unit, we divide

      Example 1:   

      mm cm

      1 mm = 1/10 cm

      Therefore, 20 mm = 20/10 cm = 2 cm

       

      Example 2:   

      dm dam

      1 dm = 1/100 dam

      Therefore, 300 dm = 300/100 dam = 3 dam

       

      Example 3:   

      cm m

      1 cm = 1/100 m

      Therefore, 150 cm = 150/100 m = 1.50 m

       

    • Download to practice offline.