Can active dry yeast be substituted for a compressed yeast cake in baking?

Yes, those cakes are typically 0.6 ounces, and when substituting you should use one packet of active dry yeast.

They are completely equivalent, with a strict conversion ratio of 1:3 (so if you have a recipe calling for 20 g of fresh yeast, you would use 6.7 g of dried, rounding up is OK). It is the same thing you are using, living organisms of the species Saccharomyces cerevisiae. The difference is in the nutritious medium in which they are packaged, it is fresh in one case and dried out in a special non-yeast-killing method in the other. Once they "wake up", they act the same way in all recipes.