Bearing# A -B =257^@#
Bearing# B -C =163^@#
#:.163^@+180^@=# bearing#color(magenta)(C-B= 343^@#
# :.color(magenta)(343^@-257^@=86^@ =angle B#
or
Bearing#color(magenta)( B - A =257^@-180^@= 77^@#
#:.color(magenta)(163^@-77^@=86^@ =angle B#
Let coords of# B# be# color(blue)(x 100.00# #color(blue)(y 100.00 #
#:.B-A=77^@# distance #257km#
#:.cos77^@xx257=57.812#
#:.sin77^@xx257=250.413#
:.coords #color(blue)(B=x 100.00# #color(blue)( y 100.00#
#:.x100.00+57.812=x157.812#
#:.y100.00+250.413=y350.413#
:.coords#color(magenta)(A=x157.812# #color(magenta)( y 350.413#
#:.B-C=163^@# distance #215km#
:.coords #color(blue)(B=x 100.00# #color(blue)( y 100.00#
#:.cos163^@xx215=-205.606#
#:.sin163^@xx215=62.860#
#:.x100.00-205.606=x-105.606#
#:.y100.00+62.860=y162.860#
:.coords#color(magenta)(C=x-105.606# # color(magenta)(y 162.860#
:.distance #A-C sqrt((x_2-x_1)^2+(y_2-y_1)^2#
:.distance #A-C sqrt((-105.606-157.812)^2+(162.860-350.413)^2#
#:.=sqrt((-263.418)^2+(-187.553)^2)#
#:.=sqrt(69389.043+35176.128)#
#:.=sqrt(104565.1707)#
#:.color(magenta)(=323.365km#
#:.(sinA)/215=(sin86^@)/323.365#
#:.sinA=(sin86^@xx215)/323.365#
#:.sin A=0.663263713#
#:.color(magenta)(angle A=41^@32'57''#
#:.sinC^@/257=(sin86^@)/323.365#
#:.sinC^@=(sin86^@xx257)/323.365#
#:.sinC^@=0.792831509#
#:.color(magenta)(angleC=52^@27'03''#
#:.86^@+41^@32'57''+52^@27'03''=180^@#