how do i get
this into radians
sin(x) = 5/13
sin(x) = 5/13
That implies you want to find angle x, not the 5/13, in radians.
5/13 is just a number here. It is the value of the sine of angle x.
If you said "find 5/13 in radians", without showing the sin(x), them 5/13 is already in radians. Or get it in decimals, 5/13 = 0.384615385. So, 5/13 = 0.384615385 radians.
Back to your equation,
sin(x) = 5/13
That is a positive sine value. Sine is positive in the 1st and 2nd quadrants, so, you'd get two answers for x if x is from 0 to 2pi radians only.
sin(x) = 5/13
sin(x) = 0.384615385
Take the arcsines of both sides,
arcsin[sin(x)] = arcsin(0.384615385)
x = arcsin(0.384615385)
Using a calculator,
x = 0.39479112 radians ---in the 1st quadrant.
x = pi -0.39479112 = 2.74680153 radians ----in the 2nd quadrant.