a) Construim inaltimile trapezului CM, DN
MN//DC
MN≡DC
MN=18
AN=MB=(24-18):2=6:2=3
ΔCMB, mM=90
mB=60⇒mC=30
MB=3⇒CB=6
ΔCMB,mM=90
MB=3
CB=6⇒Th Pitagora CM²=CB²-MB²
CM=√36-9=√27=3√3
Aria=(DC+AB)CM/2
Aria= (18+24)*3√3/2=63√3
b) ΔACB, mC=90
AB=24
CB=6⇒Th Pitagora AC²=AB²-CB²
AC²=24²-6²
AC=√576-36=540
AC=6√15