Bonjour;
a)
demi-cercle:
r= 3
(2*3,14*3)/2
=> 9,42
9,42+9+9
=> 27,42cm
b)
1/2 cercle
r= 1,5
(2*3,14*1,5) /2
=> 4,71
2,5+4,71+3+2+3+3+3+3+2,5
=> 23,71cm
