解:(1)∵∠CBD=α=60°,
∴在Rt△BDC中,
tan∠CBD=
CD
BD
.∴BD=
CD
tan∠CBD
=
10
tan60°
=
10
3
3
(m).
(2)设CE⊥AB,垂足为E,
∴CE=BD=
10
3
3
(m).在Rt△AEC中,∵tanβ=
AE
CE
,∴AE=CE•tanβ=
10
3
3
•tan20°≈2.1(m).
∴AB=2.1+10=12.1(m),即旗杆高为12.1m.
10/sin=X/sin30,X=5.77,Y/sinn20=5.77/sin80,Y=1.98,1.98+10=11.98m.
20.1