There are a variety of ways you can solve this. I'll use the sine trig function.
If the = you can simply put into a scientific calculator and press "sin-1" to get an answer of approximately 28, which means that angle R is 28°
Answer:
Y=66
X=40
Z=106
Substract '-3.4x' at LHS nad the RHS of the above expression.
Add '4' on both LHS and RHs of the above expression.
