Answer:
Use in² for area; use in³ for volume.
Step-by-step explanation:
When you calculate the area of a rectangle, you multiply length times width. Both units are in inches so:
inches × inches = (inches)² or in²
When you calculate the volume of a box (rectangular prism), you multiply length by width by height. All three units are in inches so:
inches × inches × inches = (inches)³ or in³