To convert from kilopascals (kPa) to pounds-force per square inch (psi), we can use the following conversion factor:
1 psi = 6.89476 kPa
Multiplying the given pressure of 689 kPa by the conversion factor, we get:
689 kPa * (1 psi / 6.89476 kPa) = 100 psi (rounded to the nearest whole number)
Therefore, the pressure inside the sealed tank is approximately 100 psi in pounds-force per square inch.