a)Perim=suma,tuturor,laturilor
P=8+7+5=20cm
b)P=12x3=36cm
A=bxh/2
h=6√3=>A=12x6√3/2=>A=36√3cm²
c)Ipotenuza²=cat²+cat²
Ipotenuza²=81+144
Ipotenuza²=225
Ipotenuza=15
P=15+9+12=36cm
Coboram,inaltimea,din,tr.de.ABC,si,o,notam,cu,AD.Segm.BD,format,de,aceasta,pe,ipotenuza,il,aflam,cu,t.cat.
AB²=BDxBC=>81=BDx15=>BD=81/15=27/5
Prin,diferenta,DC=BC-BD=>DC=15-27/5=>DC=48/5
Cu,t.inaltimii,aflam,AD
AD²=BDxDC=27/5x48/5
AD²=1296/25
AD=36/5
Aria=15x36/5/2=>Aria=54cm²
d)P=2L+2l=2(L+l)
P=2(9+6)=2x15=30cm
Aria=Lxl
Aria=9x6
Aria=54cm²