Use pythagorean theorem

to find the opposite side, which is 7.3
so then you can just use inverse sinA=7.3/10 which equals 46.9 degrees
I'm guessing that this is a problem to find the weight of a 90kg mass on a planet where the acceleration of gravity is 4 m/s^2. (Much less gravity than Earth, a little more than Mars.)
Just do the multiplication, and you get
360 Newtons.