la b) nu sunt 100% sigura daca ar fi corect deci fac doar la a)
fie AE perpendicular pe BC, DF perpendicular pe BC, AE si DF-inaltimi in trapez
BE=FC= BC-AD/2=18-6/2=6cm
tg<B= AE/BE=> 1=AE/6=> AE=6cm
in ABE, <E=90⁰=>AB²= AE²+EB²=>AB²=6²+6²=>AB²=36+36=>AB=rad72=6rad2 cm
Ptrapez= AD+BC+AB×2=6+18+6rad2×2= 24+12rad2 cm
