SOLUTION: **im just wondering if someone can help me out with this trig. problem...i really dont know what to do and its due tomorrow!... thanks A window in a building is 18m above the g

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Question 25074: **im just wondering if someone can help me out with this trig. problem...i really dont know what to do and its due tomorrow!... thanks
A window in a building is 18m above the ground. From this window, the angle of elevation to the top of the building across the street is 40degrees and the angle of depression to the bottom of the building across the street is 42degrees. How tall is the building across the street? Include a labelled diagram with your solution.
Answer by venugopalramana(3286) About Me  (Show Source):
You can put this solution on YOUR website!
A window in a bulinging is 18m above the ground. From this window, the angle of elevation to the top of the building across the street is 40° and the angle of depression to the bottom of the building acress the street is 42°. How tall is the building across the street? Include a labelled diagram with you solution
I AM GIVING A GRAPH BELOW FOR YOUR GUIDANCE.YOU CAN COMPLETE THE DRAWING AND LABEL THE DIAGRAM ON THE BASIS GIVEN BELOW.
LET O BE THE ORIGIN;LET THE Y AXIS BE THE BUILDING , THE WINDOW AT 18M.ABOVE GROUND BE ON THE Y AXIS AT W ; AND X AXIS THE GROUND.
HENCE OW = 18 M.
THE LINE OF ELEVATION OF TOP OF THE BUILDIND ACROSS THE STREET FROM WINDOW ON Y AXIS IS SHOWN BY WT;AND THE LINE OF DEPRESSION OF THE BUILDING FROM THIS WINDOW IS SHOWN BY WB.JOIN BT WHICH WILL BE PERPENDICULAR TO THE GROUND OR X AXIS.DRAW A HORIZONTAL W H FROM WIDOW W TO BUILDING LINE BT.
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WE HAVE 2 RIGHT ANGLE TRIANGLES WTH AND WHB.IN TRIANGLE WTH
ANGLE TWH = 40 DEGREES THE ANGLE OF ELEVATION
HENCE TAN 40 = TH/WH OR TH =WH * TAN 40.............I
IN TRIANGLE WHB
ANGLE HWB = 42 DEGREES THE ANGLE OF DEPRESSION.
HENCE TAN 42 = HB/WH OR WH=HB/TAN 42
BUT HB = OW =18 M ..SO..WH=18 /TAN 42.................II
SUBSTITUTING IN EQN.I WE GET
TH = 18*TAN 40 / TAN 42
SO HEIGHT OF BUILDING = TH +HB =18*TAN 40 / TAN 42 +18
=18*{(TAN 40 / TAN 42 ) + 1 }..YOU CAN SUBSTITUTE THE VALUES FOR TAN 40 AN TAN 42 AND GET