[填空题]
The diagram below shows quadrilateral ABCD wed ;sd,syp ii4z tz(o8:+ zh:;-xrkvcith side0d1uey k pi6rvu.;xd+ lengths of AD = 12 m, DC = 7 m and kur01 dived.p6u;x + yBC = 5 m. Angle $\mathrm{B}\hat{\mathrm{A}}\mathrm{D}=50^{\circ}$ and angle $\mathrm{B}\hat{\mathrm{C}}\mathrm{D}=100^{\circ}$.
A new line is drawn from B to D direct.
1.Calculate the length of this new line, BD. m
2.Calculate the size of angle $\mathrm{A}\hat{\mathrm{B}}\mathrm{D}$. $^{\circ}$
