Final answer:
The barometric pressure in atm is 0.986.
Step-by-step explanation:
The barometric pressure can be converted from mmHg to atm using the conversion factor 1 atm = 760 mmHg. To calculate the barometric pressure in atm, divide the mmHg reading by 760. In this case, the typical reading in California is 750 mmHg, so the barometric pressure in atm would be 750 mmHg / 760 mmHg = 0.986 atm.