To find the difference in the heights of Pyramid B and Pyramid A, you can write the equation for \( d \) (the difference) as follows:
\[ d = \text{height of Pyramid B} - \text{height of Pyramid A} \]
Substituting the given heights into the equation, we get:
\[ d = 137.2 - 99.2 \]
So, the final equation for \( d \) is:
\[ d = 137.2 - 99.2 \]