Explicație pas cu pas
a)∆ADBdr.BD=AD
AB²=2BD²
BD =√2/2AB=10√2/2=5√2cm
∆ADC dr.sin 60°=DC/AC
√3/2=DC/12
DC=12√3/2=6√3cm
BC=BD+DC=5√2+6√3
perimetrul=10+12+5√2+6√3=22+5√2+6√3cm
Aria=BC×AD/2
aria=(5√2+6√3)×5√2/2=25×2/2+30√6/2=
25+15√6cm²
b) CD=DB
2CD²=CB²
CD=√2/2×4=2√2cm
<A=180-75-45=60°
tg 60°=CD/AD
√3=2√2/AD
AD√3=2√2
AD=2√6/3cm
sin 60°=CD/AC
√3/2=2√2/AC
AC=2√2/√3/2=4√6/3
Perimetrul=4√6/3+4+(2√6/3+2√2)=
6√6/3+2√2+4=2√6+2√2+4cm
Aria=AB×CD/2=
