The length and breadth of a rectangular block are 25.2 cm and 16.8 cm, which have both been measurd to an accurancy of 0.1 cm find the area of the rectangular block.

Explanation

Here, `I = (25.2+- 0.1) cm, A = ?`
Now, `A = I xxb = 25.2xx16.8 = 423.36 cm^2 = 423.4 cm^2` ("rounding off to one decimal place")
`(DeltaA)/(A) = +- ((DeltaI)/(I)+(Deltab)/(b)) =+-((0.1)/(25.2) +(0.1)/(16.8)) = (4.2)/(423.36)`
`Deltaa = +-(4.2A)/(423.36) = +-4.2 cm^2`
Hence, area of block ` = (423.4 +- 4.2)cm^2`