Please answer these few questions on circumference will give BRAINLIEST if correct

Answer:
1) 5.6 x 2 = 11.2
2) 3.8 / 2 = 1.9
3) 6.8 / 2 = 3.4
4) 2.3 x 2 = 4.6
Step-by-step explanation:
In my knowledge
1. C ≈ 35.19mm (r=5.6mm)
C=2πr=2·π·5.6 ≈35.19mm
2. C= 2πr (C= 3.8cm)
r= C/2πr = 3.8/2·π = 0.6cm
r= 0.6cm
3. C= 2πr (C= 6.8m)
r= C/2πr = 6.8/2·π = 1.08m
r= 1.08m
4. C= 14.45m (r= 2.3m)
C=2πr=2·π·2.3≈14.45m
Hope It Helps :)