In real life, for the most part, bra sizing is straight forward.
In the US, it's a number/letter combination using inches - for example: 34B, 32C, 36D. The number is the circumference in inches of the person's ribcage just below their breasts. Then subtract that from the circumference in inches of the measurement around the body including the breasts. For every inch, it's a later letter in the alphabet: 1 inch = A, 2 inches = B, 3 inches = C, 4 inches = D, and so on. For those on metric, it's similar - just with centimeter conversions. Again, for the most part.
So, with Leslie, she's 32M. Amira is 32P. Both have the same ribcage size (band size for the bra) at 32 inches. The letter P is 3 letters later than M, so Amira's breasts are slightly larger than Leslie, relatively. However, because both are so large, already --- it may not be apparent without exaggeration in art.
Though, again, this is a cartoon world - real life does not need to apply. For example, Leslie's measurements shows a difference of 13 inches, but the actual measurement of 48 bust minus 32 band is 16 inches and Amira's 50 bust means the difference is 18 inches.
And what I just shared could be learned by using the power of the internet - if you did not already know the info.
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