Area converter
Nine units of area at once. The one worth memorising is that a hectare is 10,000 square metres and roughly 2.47 acres; the two units most land is described in.
How to convert area
Area factors are the square of the length factors, which is why the numbers look unfamiliar even when the length conversion is one you know well. A foot is 0.3048 metres, so a square foot is 0.3048²: about 0.0929 square metres, not 0.3048. That squaring is also why a room twice as long in each direction has four times the floor. The acre is the historical oddity: originally the area a yoke of oxen could plough in a day, it settled at 4,840 square yards, which is why it has no round relationship to anything metric.
Questions
About 2.471. A hectare is exactly 10,000 square metres; the acre is 4,840 square yards.
About 10.764: the square of 3.2808 feet per metre.
Because area is two-dimensional. The factor is squared: a foot is 0.3048 m, a square foot 0.0929 m².
The area a yoke of oxen could plough in a day. It settled at 4,840 square yards, which is why it fits nothing metric neatly.
A full-size pitch is roughly 0.7 hectares, or about 1.76 acres; a useful sanity check on land figures.