三、1.

xAB xB xA 2192.45 2186.29 6.16 .40 1383.97 172.43 yAB yB yA 1556

.83 2186.29 113.54 xAC xC xA 2299

.80 1383.97 80.17 yAC yC yA 1303

AB yAB172.43

arctan27.99 87°57´14″ xAB6.16

AC yAC 80.17360-35°13´48″=324°46´12″

arctan( 0.706) xAC113.54

DAB x2AB y2AB 6.162 172.432 29770.05 172.54

DAC x2AC y2AC .542 ( 80.17)2 .56 138.99

2.

hAB=1.523-1.875=-0.352m

由于hAB<0，所以A点比B点高。 HB=HA+hAB=18.763+(-0.352)=18.411m H视=HA+a=18.763+1.523=20.286m 3.