How are whole tones and semitones sized in Pythagorean tuning?

In Pythagorean tuning, the sizes of whole tones and semitones are defined as follows:

• Whole tones: All five whole tones, which represent the larger steps in the diatonic scale, are equal in size at a ratio of 9:8 (204 cents).1
• Semitones: The two semitones, representing the smaller steps, are equal in size at a ratio of 256:243 (90 cents).1

In this system, the semitones are significantly smaller than half the size of the whole tones. This specific Pythagorean semitone is also known as a limma. While this tuning system is considered melodically satisfactory, it is noted for making major thirds and sixths sharp, which can result in dissonance when notes are sounded simultaneously.12