1. C阴=πr 3.14×6=18.84(cm) S阴=S半圆-S正 314×6²÷2-6×6 =56.52-36 =20.52(cm²) 2. C阴=C正方形+πr 8×4+3.4×8 =32+25.12 =57.12(cm) S阴=2×S正-S半圆 2×8×8-3.4×8²÷2 =128-100.48 =27.52(cm²)