Final answer:
The correct inequality for areas smaller than 300 ft² is 'Area < 300 ft²', which means the area must be less than 300 square feet.
Step-by-step explanation:
The inequality that models the calculation of area for all areas smaller than 300 ft² is Area < 300 ft². To solve this inequality in context, it means that the measurement of the area must be less than 300 square feet to be considered smaller. As an example, if trying to determine whether a room is smaller than a given size, one would compare its area to the 300 ft² threshold using this inequality.