Explanation for Question 17 From the Math (No Calc) Section on the Official Sat Practice Test 4
Now for number 17, we're told that the sine of X is 0.6. 2 Well, let's change that to a fraction, right? Let's say that six over 10. 3 And we know that sign is equal to opposite over hypotenuse, 4 right? And so that means our office, that side of X is going to 5 be six because that's, our numerator are opposite and our hypotony is 6 going to be 10. So now we filled in a couple of sides on 7 our triangle, and we're told that we're interested in finding the co-sign of Y 8 and co-sign is equal to adjacent over-hype hot news, 9 right? We look at why our adjacent is six. 10 Our hypotony says 10. So our answer is 0.6 because the co-sign of 11 Y will be the same as the sine of X. 12 And the key to that here, some background information that you can know and 13 you use for other problems is that X plus Y in this case is 14 90 degrees, right? Cause we have a 90 degree angle here and an entire 15 triangle as up to 180. So X and Y are what we call complimentary. 16 They add up to 90 degrees. And whenever you have two angles that are 17 complimentary, the sign of one of them will always be equal to the co-sign 18 of the other one. And so that's just something you can memorize to help 19 you do these problems more quickly and save time without doing the math.