For this case we have that by definition of trigonometric relations of a rectangular triangle that, the sine of an angle is given by the opposite leg to the angle on the hypotenuse of the triangle.
That is to say:
[tex]Sin (30) = \frac {IR} {14}[/tex]
We clear the length of the leg:
[tex]IR = 14 * sin (30)\\IR = 14 * \frac {1} {2}\\IR = 7 \ in[/tex]
Answer:
[tex]IR = 7 \ in[/tex]
