d = 12cm => r = 12cm/2 = 6 cm
A = πr² = 36π cm²
L = 2πr = 12π cm
d = 2r = > r = 20m/2 = 10 m
A = πr² = 100π m²
L = 2πr = 20π cm
d = 2r => r = 7dm/2 = 3,5 dm
A = πr² = 12,25π dm²
L = 2πr = 7π dm
d = 2r => r = 5m/2 = 2,5 m
A = πr² = 6,25π m²
L = 2πr = 5π m