Răspuns:
Explicație pas cu pas:
Trapezul este isoscel.
NB=AB-DC=102-48=54/2=27 AN=102-27=75
ΔADC≅ΔNBC (UC) ∠A=∠B SI AD=BC
AD/NB=ND/NC=AN/BC AD/27=75/BC BC²=27×75=9×3×3×25 BC=3×3×5=45
In ΔNBC NC²=BC²-NB²=45²-27²=(45+27)(45-27)
NC=√72×18=√9×8×2×9=9×4=36
ND²=CD²+NC²=48²+36²=2304+1296=3600 ND=60