ProblemA=πr2, r=7A = \pi r^2,\ r = 7A=πr2, r=7Step-by-step solutionÁp dụng: A=πr2A = \pi r^2A=πr2.Thay r=7r = 7r=7: A=π⋅72=49πA = \pi \cdot 7^2 = 49\piA=π⋅72=49π.Tính gần đúng: 49π≈153,9449 \pi \approx 153{,}9449π≈153,94.AnswerA=49π≈153.94A = 49\pi \approx 153.94A=49π≈153.94Want to solve a different problem? Open the area solver →Related worked examples/solve/geometry/area-rectangle-5-by-8