QR question

[299678]

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Jessica sits on the top of 150 ft tower overlooking the sea. suddenly she sees a boat in distress. If the angle of depression of the boat is 6 degree, how far is the boat from the base of Jessica tower?

Given
sin 6 = 0.10
cos 6 = 0.99
tan 6 = 0.11

Answer is 1364

 

[herkulease]

So draw out your triangle
Angle of depression being 6 tells you that angle created by jessica's line of sight down to the boat is 84 degrees. We already have know we have a 90 degree angle where the tower meets the water. Do the math and you'll see that the boat's angle of elevation would also 6 degrees. Yes I easily could've told you that but sometimes they can mix it up and give you the tan/cos/sin values for 84 instead of 6 degrees.

So from the boats point of view we are given the Opposite of 150ft and need to determine the adjacent length.

So we just the Tan function. We're already given that Tan = .11

so now we just plug it the numbers and solve .11 = 150/x

x = 150/.11

x = 1363.63 or 1364

 

[UndergradGuy7]

kpark, remember SOH CAH TOA. Sine is opposite over hypotenuse. Cosine is adjacent over hypotenuse. Tangent is opposite over adjacent.

 

[dentalWorks]

You might find this website helpful: http://www.mathsrevision.net/gcse/pages.php?page=39