№1. Given: r=8 ft, π≈3.14
C=2×π×r=2×3.14×8=50.24=50.2 ft
A=π×r²=3.14×64=200.96=201 ft²
Answer: 50.2 ft; 201 ft²
№2. Given: D=11 cm, π≈3.14
d=2r or r=2/d, so if d is 11 cm, then r is 11÷2=5.5 cm
C=2×π×r=πD=3.14×11=34.54=34.5 cm
A=π×r²=3.14×(5.5)²=94.985=95 cm²
Answer: 34.5 cm; 95 cm²