Question

A lighthouse is located on an island 200 feet from the shore of the mainland as

shown. If x=0.29 rad, what is d?

Answer 1

Answer: Approximately d = 208.72

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Work Shown:

Make sure your calculator is in radian mode

A quick way to check is to compute cos(pi) and you should get -1

cos(angle) = adjacent/hypotenuse

cos(x) = 200/d

cos(0.29) = 200/d

d*cos(0.29) = 200

d = 200/cos(0.29)

d = 208.715135166392 which is approximate

d = 208.72

I rounded to two decimal places since x is rounded in that manner as well. Round however else you need if your teacher instructs.