Answers:

1. 18.8cm²

2.53.4cm²

3.75.4cm²

4.50.2cm²

5.70.7cm²

Explenation:

Formula in finding Circumference using radius:

C=2πr

Formula in finding Circumfernce using diameter:

C=πd

Solutions:

1.C=2x3.14x3cm

C=18.84cm² or 18.8cm²

2.C=2x3.14x8.5cm

C=53.38cm² or 53.4cm²

3.C=2x3.14x12cm

C=75.36cm² or 75.4cm²

4.C=3.14x16cm

C=50.24cm² or 50.2cm²

5.C=3.14x22.5cm

C=70.65cm² or 70.7cm²