3 diametre=AG=120m⇒un dioametru=120:3=40m=2raze⇒o raza=20m
(sau direct de pe s desen AG=6 raze⇒o raza=120:6=20m)
b) aria suparfetei hasurate =3 dreptunghiuri (40*20)-3 semicercuri raza 20 +unpatrat latura 40=
3(40*20-π*20²/2)+1600m²=
3(40*20-200π)+1600=
3*100(8-2π)+1600=600(4-π)+1600=
=200(12-3π+8)=200(20-3π)m²≈2115,04m²
