ABCD trap isoscel cu un unghide 60°si bazamare=2baza mica⇒ABCD compus din 3 tr.ecchilaterale, AC⊥BC si AD⊥BD
AM⊥(ABC)
AD⊥BD
AD siBD⊂(ABC)⇒T3p⇒MD⊥BD, d(M, BD)=MD
MD=√(AM²+AD²)=√(4²+10²)=√116
b)
AM⊥(ABC)
AC⊥BC
AC si BC⊂(ABC)⇒T3p⇒MC⊥BC
⇔ΔMCB dreptunghic in C⇔Arie CB*MC/2
CB=10
MC=√AM²+AC²
AC=2 inaltimide tr echilat cu lat.de10=10√3
MC=√(4²+(10√3)²)=√316=2√79
arie MCB= 2√79*10/2=10√79 cm ²
