If a circular piece of tin has a measured radius of 2.6 cm . What is circumference ?

Explanation

`r=2.6` cm
Circumference of circular disc `= 2pir`
`=2 xx 3.1428 xx 2.6`
Here 2.6 has only 2 significant digits. Hence in the above multiplication `pi` value should be written with `2+1 =3` significant figures.
`pi=3.1428=3.14`
Circumference`= 2 xx 3.14 xx 2.6`
`= 16.328`
This is to be rounded off to 2 significant digits. Circumference is 16cm.