Answer
$25.5 \text{ acres}$
Work Step by Step
Convert by multiplying $\dfrac{1 \text{ acre}}{0.4 \text{ ha}}$ to obtain:
$\require{cancel}
=10.2 \cancel{\text{ ha}} \cdot \dfrac{1 \text{ acre}}{0.4 \cancel{\text{ ha}}}
\\=\dfrac{10.2}{0.4} \text{ acre}
\\=25.5 \text{ acres}$
