a light house is 20 m height and observe on the top of the light house observe a boat from the observer ? B
Answers
Answered by
1
Answer:
Answer
Let AB is a 20 M high light-house and a ship is at the point C.
According to the question
AB=20 m,∠DBC=∠ACB=30
∘
In △ABC
tan30
∘
=
AC
AB
3
1
=
x
20
x=20
3
x=20×1.732
x=34.64 metres
So, the distance between lighthouse and ship is 34.64 meters.
Answered by
0
Answer:
Let the observer be at O, the top of the lighthouse PO.
It is given that PO = 100 m and the angle of depression from O of A and B are 30
∘
and 45
∘
respectively.
∴∠OAP=30
∘
and∠OBP=45
∘
In Δ OPB, we have
tan45
∘
=
BP
OP
⇒1=
BP
100
⇒ BP = 100 m
In Δ OPA, we have
⇒tan30
∘
=
AP
OP
⇒
3
1
=
d+BP
100
⇒ d + BP = 100
3
⇒ d + BP = 100
3
⇒ d = 100
3
- 100
⇒ d = 100(
3
- 1) = 100(1.732 - 1) = 73.2 m.
Hence, the distance travelled by the ship from A to B is 73.2 m.
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