# Finding the angle from sin(2 theta)=0.348

1. Mar 20, 2013

I was wonder how to find the second angle to this problem. I already know one of the angle is 10.2 degree but shouldn't the the second angle be 180-(2*10.2) since in the second quadrant, sin values are positive but in the book, it's given as 90-10.2. Is it something to do with the properties of (2 theta)?

Last edited: Mar 20, 2013
2. Mar 20, 2013

### vela

Staff Emeritus
Let x=2θ. Then you have sin x = 0.348, so x=20.4 or x=180-20.4. Now write x in terms of θ and solve.