3rd Class Mathematics Measurement Length, Weight and Capacity Measurement of Shorter Length

         Measurement of Short Length

The shape and size of everything are measured by a measuring instrument. Rulers    are well known devices for the measurement of the length. Measured lengths are expressed in units. The units for measured length are kilometre, metre, centimeter and millimetre. Sl unit for the measured length is metre. Small lengths are measured in metre, centimetre and millimetre. The length of our one finger is measured in inches or in centimetre or in millimetre but the length between two city is measured in kilometres. 1 metre = 100 cm and 1000 m = 1 kilometer.

Units are given in the options for the measurement of the length. Which one of the following units is not used for the measurement of the length?

(a) Centimeters

(b) Kilometers

(c) Kilograms

(d) None of these

(e) All of these

Answer (c)               

Explanation

Kilogram is the Sl unit of mass hence, this is not used for the measurement of length.

                Conversion Table     

Convert 45 metres into centimetres and choose the correct answer from the following options:

(a) 5400cm

(b) 4500cm

(c) 240cm

(d) None of these

(e) All of these

Answer (b)

Explanations    

             Conversion between Metres and Centimetres

The following steps are used for the conversion of metres into centimeters and centimetres into metres:

Step 1:   Metres are converted into centimetres by multiplying 100.

Step 2:   Centimetres are converted into metres by dividing 100.

Convert 225 meters into centimeters and 3445 centimeters into meters.

(a) 22500 cm, 34.45 m

(b) 4500 cm, 32.34 m

(c) 2250 cm, 30.45 m

(d) None of these

(e) All of these

Answer (a)

Explanations  

             Conversion of Mixed Units into Single Unit

The following steps are used for the conversion of mixed units into singleunit:                                                                       

Step 1:   Arrange the given units in descending order.                         

Step 2:   Convert metres into centimetres by multiplying 100.                   

Step 3:   Convert centimetres into metres by dividing 100.                      

Step 4:   Add them and express the sum in single unit.

Convert 85 m 55 cm into centimeters.

(a) 2500cm

(b) 8500cm

(c) 8555cm

(d) None of these

(e) All of these

Answer (c)

Explanations

85 m is in meter therefore, it should be converted into centimeters by multiplying  but 55 cm remains in cm. Sum of 8500 cm and 55cm = 8555 cm is their conversion from mixed fraction meter and centimeter into centimeter.    

              Conversion of Length in Decimal Numbers

The following steps are used/or the conversion of length in decimal numbers into length in whole numbers:

Step 1:   Identify the given length in decimal number is in metres or centimetres 1

Step 2:   Multiply by hundred if the length is in metre.                       

Step 3:   Divide by hundred if the length is in centimetre.

If the length of a wire is 56.70 m then find the length of the same wire in centimeters?

(a) 5670cm

(b) 8500cm

(c) 8555cm

(d) None of these

(e) All of these

Answer (a)

Explanation

Multiplying 56.70 m by 100 required lengths in centimeters is obtained thus  

               Conversion of Mixed Units

The following steps are used for the conversion of mixed units of length into decimal numbers:

Step 1:   Put meters at left from the decimal point.

Step 2:   Convert centimeters into decimal numbers by dividing hundred.

Step 3:   Put centimeters which is obtained from step 2 at right from the decimal point.

Step 4:   Express the resulting decimal numbers in meter.

The side length of a table is 23 m 4 cm. Express the length of the table in decimal numbers?

(a) 32.04m

(b) 8.5m

(c) 23.04m

(d) None of these

(e) All of these

Answer (c)

Explanation

Step 1: Put metres at left from the decimal as 23.

tep 2: Convert centimetres 4cm into decimal number by dividing hundred

Step 3: Put centimetres which is obtained from step 2 at right from the decimal point = 23.04.

Step 4: Express the resulting decimal numbers in metre = 23.04 m.