Final answer:
The question requires additional information on the dimensions of the cake or the distribution of frosting to calculate the percentage of the surface area that is chocolate. Given the references are unrelated to a mathematical context, the question cannot currently be answered accurately.
Step-by-step explanation:
The question is asking for the percentage of the surface area that is covered with chocolate frosting on a layer cake. To answer the question effectively, we would need more information regarding the dimensions of the cake or the method used to apply the frosting. If these were provided, one could calculate the surface areas covered by both vanilla and chocolate frostings using geometric formulas, then divide the area covered by chocolate by the total frosted surface area (excluding the bottom) and multiply by 100 to get a percentage.
However, based on the supplied references, we do not have sufficient geometric or proportional data to answer this particular math problem. References to cake appear linked to artworks or recipes that don't provide the necessary mathematical context. Should geometric data of the cake be made available, we would apply concepts of geometry including the areas of circles, rectangles, or other relevant shapes to deduce the answer.
Without this information, it's not possible to provide a precise percentage or solve the problem.