Problem 10
Answer: approximately 57.39159 km
Explanation: You'll use the equation cos(28) = d/65 to solve for d to get d = 65*cos(28) = 57.39159 approximately. We use the cosine ratio because it ties together the adjacent and hypotenuse.
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Problem 11
Answer: approximately 10.46162 meters
Explanation: This time we use the sine rule. We have the height as the opposite side (which is unknown, call it x) and the hypotenuse is the ladders length (11). So we have sin(72) = x/11 which solves to x = 11*sin(72) = 10.46162
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Problem 12
Answer: approximately 16.05724 cm
Explanation: Now we use the tangent rule to connect the opposite and adjacent sides.
tan(37) = 12.1/x
x*tan(37) = 12.1
x = 12.1/tan(37)
x = 16.05724 approximately
