The radius of a sphere is measured to be `(2.1+-0.5)` cm. Calculate its surface area with error limits .

Explanation

`r = (2.1 +- 0.5)cm, A = ?`
`A = 4pi r^2 = 4xx(22)/(7)(2.1)^2 = 55.44cm^2`
`(DeltaA)/(A) = +- (2Deltar)/(r ) = +- (2xx0.5)/(2.1) = +-0.476`
`DeltaA = +- 0.476 A = +- 0.476xx55.44 = 26.4 cm^2`
Hence, surface area of sphere` = (55.4+- 26.4)cm^2` (rounding off to one place of decimal)