1)花圃周长= π×d
= π×20.5×2
= 41π
≈128.74(m)
128.74÷1.5 ≈85.8
答:至少可以摆85盆花
2)花圃面积= π×r×r
= π×20.5×20.5
= 420.25π
≈1319.59(m²)
1319.59×2=2639.17(元)
答:植完整个草坪需要2639.17元
3)花台面积= π×R×R - π×r×r
= π×(20.5+0.5)×(20.5+0.5)- π×20.5×20.5
= π×21×21 - π×20.5×20.5
= 441π - 420.25π
= 20.75π
≈65.155(m²)
65.155×8≈521.2≈522(块)
答:贴完花台至少需要522块瓷砖