from the foot of a tower 25m high the angle of elevation of the top pillar is 60degree and from the top of the tower,the angle of elevation of this top is 30 degree. find the height of the pillar?
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let AB be the tower and the tower be CD
AB=25cm
then ED=25cm
from diagram we get ED=25cm,let EC=h.
In triangleBCD we have,
tan60= CD/BD
√3=(EC+ED)/BD
BD=(h+25)/√3......................1
AE=BD=(h+25)/√3
in triangle AEC we have,
tan30=EC/AE
tan30=h/(h+25)/√3
1/√3=h×√3/(h+25)
1/√3=√3h/(h+25)
h+25=3h
2h=25
h=12.5
Hence height of pillar=EC+ED=h+25=12.5+25=37.5m
AB=25cm
then ED=25cm
from diagram we get ED=25cm,let EC=h.
In triangleBCD we have,
tan60= CD/BD
√3=(EC+ED)/BD
BD=(h+25)/√3......................1
AE=BD=(h+25)/√3
in triangle AEC we have,
tan30=EC/AE
tan30=h/(h+25)/√3
1/√3=h×√3/(h+25)
1/√3=√3h/(h+25)
h+25=3h
2h=25
h=12.5
Hence height of pillar=EC+ED=h+25=12.5+25=37.5m
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