Răspuns:
Explicație pas cu pas:
i)x= 50° alterne interne
ii) y=50°+90°=140° unghi exterior
2)a)
i)AB=2r=6 cm
ii)(AB)=180°
iii)∡AOC=70°
iv) ∡BOC=180°-70°=110°
b)5/6=x/2 ⇒ x=5/3
Subiectul II
1) total bile 15+35=50
probabilitatea bilei albe=15/50=3/10
2)x/5=y/7=z/12(=(z-x)/(12-5)=49/7=7
x=35 ; y=49 ;z=12·7=84
3)
6 munc..............................8h
16 munc.............................x=6×8/16=3 h
4)
x+20+2x+3x-20=360 ⇒6x=360° x=60°
∡AOB=60°+20=80°
∡BOC=120°
∡COA=3·60-20°=160°
∡DOC=160°-120°=40°
