Răspunsuri

2014-04-12T17:33:49+03:00
Duci BM_/_CD (baza mare)
ΔDMB mas<M=90  mas<D=30  ⇒ cos<D=MD/BD=√3/2
MD=CN =CD-DM/2=CD-AB/2=12-6/2=6/2=3
CN_/_CD

3/BD=√3/2
BD=3*2/√3  rationalizam cu√3
BD=6√3/3=2√3
BD=AC=2√3

BM²=BD²-MD²=(2√3)²-3²=12-9=3⇒  BM=√3

A=(B+b)*h/2=(6+12)*√3/2=18*√3/2=9√3