1. dreptunghi
2.isoscel
3.patrat
4. 132° (=180°-48°)
5.
L=2l
P=2(L+l)=2(2l+l)=2×3l=6l=48cm
=>l=48cm:6=8cm
=>L=2×l=2×8cm=16cm
6. 120°
(daca o diagonala este congruenta cu o latura a rombului, atunci rombul "e format din 2 triunghiuri echilaterale" )
7. x, y masura a doua unghiuri (alaturate) a unui paralelogram
{x,y} d.p. {5, 13}
=>x/5=y/13=(x+y)/(5+13)=180°/18=10°
=>x=5×10°=50°
=>y=13×10°=130°
8. A ABCD=64cm^2
ABCD patrat => l=¬/(64)=8(cm)
P ABCD=4×l=4×8cm=32cm
9.AC=6cm
AC+BD=?
ABCD dreptunghi =>[AC] congruent cu [BD] =>AC=BD=6cm
=>AC+BD=6+6=12(cm)