Final answer:
When volume is constant, pressure is directly proportional to temperature. When pressure is constant, volume is directly proportional to temperature.
Step-by-step explanation:
When volume is constant, pressure is directly proportional to temperature. When pressure is constant, volume is directly proportional to temperature. These relationships are known as Amontons's law and Charles's law respectively. For example, if the temperature on the Kelvin scale increases by a certain factor, the gas pressure also increases by the same factor.