Answer: Choice C
7 divided by cosec 50 degrees
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Explanation:
Abbreviations:
sec = secant
cot = cotangent
cosec = cosecant (csc is also a widely used abbreviation)
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Let the horizontal leg be x
This leg is opposite the angle 50 degrees. The hypotenuse is 7
Opposite = x
Hypotenuse = 7
We'll either use the sine rule or the cosecant (csc) rule
sine = opposite/hypotenuse
cosecant = hypotenuse/opposite
Since "sine" is nowhere to be found in the answer choices, we'll use the cosecant rule
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cosecant = hypotenuse/opposite
csc(angle) = hypotenuse/opposite
csc(50) = 7/x
x*csc(50) = 7
x = 7/csc(50)
This is why the answer is choice C
Substitute x = 5 in the equation.
Therefore, the answer is -15 or last choice when x = 5.
