Answer
$100\;cm^2$.
Work Step by Step
Total number of spaces inside the plate$=16\times 25=400$.
Let the actual measurement is $=x$.
Area of one square $=0.25\;cm^2$.
$\Rightarrow \frac{scale \;measurement \;1}{actual\;measurement\;1}=\frac{scale \;measurement \;2 }{actual\;measurement\;2}$
$\Rightarrow \frac{1\;space}{0.25\;cm^2}=\frac{400\;spaces}{x}$
Cross multiply.
$\Rightarrow x=100\;cm^2$.
