bonjour,
figure 1 :
A = ok
P = 2*5,20 + (2*pi*1,50)
= 10,4+3pi
= 10,4+9,42 = 19,82cm
figure 2 :
P des 2 petits cercles = pi*2*r
= pi*2*1,60 = 10,048 = 10cm
A = pi*r² = pi*1,6² = 8,0384 = 8cm²
figure bleue =
P = pi*2*3,2- P petits cercles = 20,096-10 = 10cm
A = pi*r²- A petits cercles = pi*3,2²-8 = 24,1cm²
