ProblemA=s2, s=9A = s^2,\ s = 9A=s2, s=9Step-by-step solution正方形的面積：A=s2A = s^2A=s2。代入 s=9s = 9s=9：A=81A = 81A=81。AnswerA=81A = 81A=81Want to solve a different problem? Open the area solver →Related worked examples/solve/geometry/area-rectangle-5-by-8