Question 885171
A 200 metres × 200 metres 
 B 2 hectares 
 C 3 acres 
 D 30 000 square metres
<pre>
[Here in the US, we spell it "meters".]

Get them all to the same units.  The first one is

{{{matrix(1,2,200,meters)}}}{{{"×"}}}{{{matrix(1,2,200,meters)}}} {{{""=""}}} {{{matrix(1,3,40000,square,meters)}}}.

So we know A is bigger than D.

1 hectare is 10000 square meters, so 2 hectares is 20000 square meters,

so A is still the biggest so far.

Now we must check C.

1 acre = 4046.9 square meters.

So 3 acres is 3×4046.9 = 12140.7 square meters.

So the biggest area is A.

Edwin</pre>