@abelenky's answer is correct if you're on the ground and therefore have time to look up figures and do the math. If you're in the air, the rule of thumb for light aircraft (with a typical glide ratio of 8:1) is 1.5nm per 1,000ft AGL, after subtracting 1,000ft or so for flying a pattern around your landing site. Rounding 9,842ft to 10,000ft, that gives a gliding range of 9×1.5=13.5nm, which is close enough in an emergency.
Note that the Vg (if any) given in your POH assumes max gross weight; if you're lighter, your best glide speed decreases and your gliding range increases. And of course, that all assumes no wind, which is unlikely in the real world; you'll generally want to glide downwind (to maximize range) and then do a 180 to land with a headwind, which is covered by the 1000ft subtracted above for the pattern.