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Adnan states if cos30°≈0.866 then sin30°≈0.866

Which justification correctly explains whether or not Adnan is correct?

 Mar 17, 2019
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The first answer is corect

 

This is because cos(x) = sin(90-x) in a right traingle. (If you want to see how this works, I suggest making a right triangle with an angle x and make the other angle 90-x (bc all angles add up to 180 in a triangle (x+(90-x)+90 = 180)) and then using soh cah toa, find the sin of x  and the cos of 90-x  (in terms of opposite side, adjacent side, and hypotenuse)

 

so sin(90-30) would be equal to cos(30)

so sin(60) = cos(30), not sin(30) = cos(30)

 Mar 17, 2019

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