Answer:
Step-by-step explanation:
The piece of cardboard is 12.0 cm long and 6.3 cm wide.
1 centimeter = 10 millimeters
Therefore,
12 centimeters = 12 × 10 = 120 millimeters
6.3 centimeters = 6.3 × 10 = 63 millimeters
The cardboard is rectangular and the formula for determining the area of a rectangle is expressed as
Area = length × width
Therefore, the area of the cardboard is
120 × 63 = 7560 millimeters²