Select the correct answer from each drop-down menu. cos(420°) = sin(450°) =

420 degrees is coterminal with 60 degrees. They point in the same direction. Note how 60+360 = 420. Adding a full revolution onto 60 degrees has us land on 420

So cos(420) = cos(60) = 1/2 using either a calculator, table, or the unit circle. 

Similarly, 
sin(450) = sin(90) = 1
the angles 90 degrees and 450 degrees point directly north in the same direction. This is why they are coterminal angles. Mathematically, 90 + 360 = 450



In short,

cos(420) = 1/2
sin(450) = 1