Answer:
Explanation:
Use SOH CAH TOA to recall how the trig functions fit on a triangle 
SOH: Sin(Ф)= Opp / Hyp 
CAH: Cos(Ф)= Adj / Hyp 
TOA: Tan(Ф) = Opp / Adj
well you know it's a 90° so do you know what Sin(90) is? you should :D
I think this is kinda a trick question too b/c Opp here is also Hyp 
so it would like like sin(90) = Opp / Hyp but that's 427/427 for this question. seems kinda confusing why ask it that way.. huh :/
sin(90) = 1