tolong dong besok dikumpulin nih

r = d : 2 = 50 : 2 = 25
keliling = phi kali r kali 2
= 3,14 kali 25 kali 2
= 157 cm2

r = 45 : 2 = 22,5
keliling = 3,14 kali 22,5 kali 2
= 141,3 cm2

r = 80:2=40
keliling = phi kali r kali 2
= 3,14 kali 40 kali 2
=25,1 cm²

r = 35:2=17,5
keliling = 3,14 kali 17,5 kali 2
= 109,9 cm2

c. pi x diameter = 3,14 x 50 = 157 cm
d. pi x diameter = 3,14 x 80 = 251,2 cm
e. pi x diameter = 3,14 x 45 = 141,3 cm
f.  pi x diameter = 22/7 x 35 = 110 cm

semoga membantu :v