Angela Wozniak, age 11, of San Diego, Calif., for her question:

HOW BIG IS AN ACRE?

An acre is a measure of land. It is made up of 43,560 square feet, or 4,840 square yards, or 160 square rods.

An acre that is square in shape has about 208.7 feet on each side.

There are 640 acres in a square mile.

In the metric system, an acre equals 4,047 square meters. One hectare, a metric measure, is equal to 2,471 acres.

In the city, many subdivisions are made up of lots that measure 50 by 125 feet. The land from seven lots this size would measure just a bit over one acre.

An acre foot is a measure of water volume. It

equals the volume of a square container one foot high with a base one acre in area. This corresponds to 43,560 cubic feet.