**Definitions:**

**Double Square Foot** (abbreviation: **ft4**): is an imperial unit and U.S. customary unit (non-SI, non-metric) of area moment of inertia, a geometrical property of an area which reflects how its points are distributed with regard to an arbitrary axis.

**Double Square Millimeter** (abbreviations: **mm4, or mm 4**): is the SI derived unit of area moment of inertia, a geometrical property of an area which reflects how its points are distributed with regard to an arbitrary axis.

## How to Convert Double Square Feet to Double Square Millimeters

*Example: How many double square millimeters are equivalent to 88.47 double square feet?*

As;

1 double square feet = 8630974841.2416 double square millimeters

88.47 double square feet = Y double square millimeters

Assuming Y is the answer, and by criss-cross principle;

Y equals 88.47 times 8630974841.2416 over 1

(i.e.) Y = 88.47 * 8630974841.2416 / 1 = 763582344204.64 double square millimeters

Answer is: 763582344204.64 double square millimeters are equivalent to 88.47 double square feet.

*Practice Question: Convert the following units into mm4:*

N.B.: After working out the answer to each of the next questions, click adjacent button to see the correct answer.

( i ) 35.7 ft4

( ii ) 67.09 ft4

( iii ) 9.74 ft4