SOLUTION: If sin a = 0.2 then cos a must equal?

Question 323917: If sin a = 0.2 then cos a must equal?
Answer by Edwin McCravy(20086) (Show Source): You can put this solution on YOUR website!


If sin a = 0.2 then cos a must equal?

Since  and since

 the fraction  if we draw a right triangle
with one side equal to the numerator  of that fraction and the
hypotenuse equal to the denominator of that fraction , then the
angle that the side that equals  is opposite to will be angle a:


 
Since  all we need
do is calculate the side adjacenet to angle a, which is the bottom side,
call it x.



We use the Pythagorean theorem to calculate x:













So 

The decimal value of that is 0.9797958971, and you can get that
just by using your TI-84 calculator

cos(sin^-1(0.2))
     .9797958971  

Edwin

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