Page 133 - Revised Maths Wisdom Class - 3

Length 131

Measuring tape is also used to measure lengths in day-to-day life.
Carpenters, tailors, etc. all use measuring tapes to measure the
length.

Metre rod: When you visit a shop to buy ribbons, fabrics etc., the
shopkeeper uses a rod called metre rod to measure the length.

Conversion of Length

1 m = 100 cm 1 km = 1000 m
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● To convert metres into centimetres, multiply the value in metres by 100.

For example, 7 m = (7 × 100) cm = 700 cm
8 m 72 cm = (8 × 100) cm + 72 cm = (800 + 72) cm = 872 cm.

● To convert kilometres into metres, multiply the value in kilometres by 1000.

For example, 5 km = (5 × 1000) m = 5000 m
8 km 70 m = (8 × 1000) m + 70 m = 8000 m + 70 m = 8070 m

● To convert metres into kilometres and metres, separate the thousands and write the
answer.

For example, 5008 m = 5000 m + 8 m = 5 km 8 m (1000 m = 1 km)

7926 m = 7000 m + 926 m = 7 km 926 m

● To convert centimetres into metres and centimetres separate the hundreds and write
the answer.

For example, 625 cm = 600 cm + 25 cm (100 cm = 1 m)

= 6 m 25 cm

Exercise 10A

1 Circle the suitable unit to measure the following.

(a) Length of a mobile phone m cm km

(b) Length of your notebook m cm km

(c) Height of school building m cm km