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 = `2pi r`
` = 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.