Here I have the answer:emanuellasker said:Hey has anyone seen question 20 in the 2001 paper? How on earth do you do this.
In ABC:
tan 25 = 100/AC
AC = 100/tan25
=214.4506....m
In DBC:
tan 76 = 100/DC
DC = 100/tan76
=24.9328...m
AD = AC - DC
= 214.3406... - 24.9328...
189.5178...
=190m.
OR
In DBC:
sin 76 = 100/DB
DB = 100/sin76
= 103.0613...m
In ABD:
<ADB = 180 - 76
= 104
<ABD = 180 - 25 - 104
=52
Using the sine rule:
AD/sin 51 = DB/sin25
AD = DBsin51/sin25
=103.0613...sin51/sin25
189.5178...
=190m