Page 117 - Start Up Mathematics_3

2. Read the marking on the ruler at the other end of the object. This gives the
length of the object in centimetres.

Example 1: What is the length of the given cup coaster?

A Challenge!
Measure the length of
your foot using a 15 cm
ruler.

mm 1 cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15

6 5 4 3 2 1 1/16''

Solution: The length of the cup coaster is 4 cm.

Example 2: What is the length of the given pencil?

mm 1 cm 2 3 4 5 6 7 8 9 10 11 12 13 14 15

6 5 4 3 2 1 1/16''

Solution: The length of this pencil is between 9 cm and 10 cm. But it is closer
to 10 cm. So, we say that the length of the pencil is 10 cm.

Conversion of metres into centimetres

Some lengths cannot be measured using a 15 cm long ruler. To measure such lengths,
we use a bigger ruler called a metre ruler. A measuring tape is of the same length as
a metre ruler. So, it can also be used to measure bigger lengths.

Since 1 m = 100 cm, a metre ruler is 100 cm long. 1 m = 100 cm

109