解：设正方形瓷砖的边长为x200x^2=18x^2=0.09x=0.3所以，每块瓷砖的边长为0.3m
18/200=0.09m²√0.09=0.3m
18/200=0.09 m^2√0.09=0.3m
∵18×10000=200a²a²=900a=30㎝∴每块瓷砖的边长30㎝
0.3米
