It's about as big as an Apple iPad.
It's about two-fifths as big as an Airplane Tray Table.
In other words, 0.0000040020 hectares is 0.3960 times the size of an Airplane Tray Table, and the size of an Airplane Tray Table is 2.530 times that amount.(average)
With wide variation among different models of airplanes, in-flight tray tables measure around 41.2 cm (16.5 in) x 24.1 cm (9.5 in) for a total area of 0.00001010 hectares. Flight safety rules require that the tray tables be upright and locked during takeoff and landing so as to reduce the risk of passenger abdominal injury.
It's about seven times as big as a Playing Card.
In other words, 0.0000040020 hectares is 7.10 times the size of a Playing Card, and the size of a Playing Card is 0.140 times that amount.(ISO 216 B8 size)
A single ISO 216 B8-size playing card measures 0.000000560 hectares. Although this size is the most common playing card, many casinos use the smaller "bridge size" card — 0.000000260 hectares smaller.
It's about seven-and-a-half times as big as a Post-it® Note (3M).
In other words, the size of a Post-it® Note (3M) is 0.140 times 0.0000040020 hectares.(3M) (generically sticky notes, a.k.a. repositionable notes, a.k.a. repositional notes)
A Post-it® Note measures 0.000000540 hectares in total area. In September, 1989, Hurricane Hugo swept through Charleston, South Carolina with winds up to 230 kph (140 mph), uprooting eight oak trees in Mr. Bruce Brakefield's yard, but leaving in place a Post-it® note attached to his front door.
It's about one-twenty-fifth as big as a Bath Towel.
In other words, 0.0000040020 hectares is 0.036926 times the size of a Bath Towel, and the size of a Bath Towel is 27.081 times that amount.(for Fieldcrest Luxury Solid Towels)
Bath towels typically measure 142.24 cm (56 in) by 76.2 cm (30 in), for a total area of about 0.00010838 hectares. The city of Bursa, Turkey is known as the birthplace of the modern towel.
It's about 50 times as big as a Secure Digital (SD) card.
It's about 85 times as big as a Quarter.
In other words, 0.0000040020 hectares is 86.590 times the size of a Quarter, and the size of a Quarter is 0.01155 times that amount.(United States quarter-dollar coin) (a.k.a. Quarter dollar, a.k.a. Washington quarter, a.k.a. two bits)
The George Washington quarter, in circulation in various forms since 1932, has a diameter of 24.26 mm (0.955 in) and an area of 0.000000046220 hectares.