Răspunsuri

2014-04-22T19:03:09+03:00
Fie DB_/_ BC  ⇒mas<B=90
ΔDBC, mas<B=90,  BN_/_DC   ⇒BN-h
DN=AB=8
NC=DC-DN=18-8=10
BN²=DN*NC= 8*10  =80            ⇒BN=4√5

A=(AB+DC)*BN/2= (8+18)*4√5/2=  26*2√5=52√5
2 4 2