To determine how many square feet of tile Chiang and his parents need to re-tile the kitchen floor, we need to measure the length and width of the kitchen and then multiply the two values to get the area.
Let's say the kitchen is rectangular with a length of 10 feet and a width of 8 feet.
The area of the kitchen floor is:
Area = length x width
Area = 10 ft x 8 ft
Area = 80 square feet
Therefore, Chiang and his parents need 80 square feet of tile to re-tile the kitchen floor.