3) a/3=b/4=c/5=d/6=360°
a/3=k|×3=>a=3k
b/4=k|×4=>b=4k
c/5=k|×5=>c=5k
d/6=k|×6=>d=6k
3k+4k+5k+6k=18k
18k=360°|÷18=>k=20
a=3×20=60
b=4×20=80
c=5×20=100
d=6×20=120
toate înafara de 8 si 15 is asemănătoare cu 3
La 15 e 360°÷4=90
