The barometric pressure measured outside an airplane at 9 km (30,000 ft) was 259
mmHg. Calculate the pressure in kPa.
This question involves unit conversions. Taking the value of 1atm to be 760mmHg or 1.01325*105 Pa the question can be solved as below.
259mmHg* (1.01325*105 Pa/ 760mmHg) =34.5305kPa