Length

What is Length?

We can define length as the measurement of something from one end to another.

A learner can determine the length of something by its measurement. Everything in our environment has a length which includes notebooks, pens, pencils, cellular phones, doors, cars, gardens, laptops, bags, boxes and many more.

Length of an object can be measured using a measuring tape, ruler, stick, and other tools.

Units for Measurement

Units are needed to measure the length.

For example, Mary's home is 7 kilometres away from her friend’s home. Here, the measuring unit is kilometres.

Similarly, the pencil is 11 centimetres long. Here, the measuring unit is centimetres.

Both kilometres and centimetres are units of length. we use kilometres for large distances while centimetres are used for small distances.

Units for measurement for class 2 include kilometre, metre, centimetre, feet, inch, etc.

Conversion of one unit to another unit

1 kilometre = 1000 metres
1 metre = 100 centimetres
1 kilometre = 100,000 centimetres
1 foot = 12 inches

Symbols used for the units of length

Centimetres can be written as cm.
Metres can be written as m.
Kilometres can be written as km.
Foot/Feet can be written as ft.
Inches can be written as in.

The order of the units is as follows:

kilometre < metre < centimetre

Foot is greater than an inch.

Let us see a few examples to understand it better.

Example: What is the length of the toy car given below?

a) 6 centimetres
b) 7 centimetres
c) 5 centimetres
d) 9 centimetres

Answer: b) 7 centimetres

Explanation: The length of the toy car is 7 centimetres (cm) as marked on the scale.

Example: What is the sum of the lengths of the blue rope and the green rope?

a) 9 cm
b) 11 cm
c) 13 cm
d) 17 cm

Answer: c) 13 cm

Explanation: Length of blue rope = 10 − 4 = 6 cm 
Length of green rope = 15 − 8 = 7 cm
Sum of the lengths of the blue rope and the green rope = 6 + 7 = 13 cm.

Hence, option (c) is the correct answer.