Answer
$5.4 cm^2$
Work Step by Step
Area is given by: $A= Length \times Width$
The differential form can be evaluated as follows:
$dA=\dfrac{\partial A}{\partial L} \times dL + \dfrac{\partial A}{\partial W} \times dW$
Plug the values, we get
$dA=(24) \times (0.1)+(30) \times (0.1)$
$\implies dA=2.4 cm^2+3.0 cm^2$
Answer is: $dA=5.4 cm^2$