# The radius of a wire is $0.24 \;mm$ . Then its area of cross- section by taking significant figures into consideration is

$\begin{array}{1 1} 0.1 \;mm^3 \\ 0.2 \;mm^3 \\ 0.18 \;mm^2 \\0.180\;mm^2 \end{array}$

Answer :$0.18 \;mm^2$
Area of cross -section $= \large\frac{22}{7}$$\times 0.24 \times 0.24 \;mm^2$
$\qquad= 0.18 \;mm^2$