If there is 0.492grams of cocoa per 1cm3 and there are 15grams of cocoa in a tablespoon then there will be 15x0.492grams, which means there is 7.38grams of cocoa per 1 tablespoon. Since the recipe uses 7 tablespoons of cocoa(2 for the cake and 5 for the buttercream) then you will need 7.38*7=51.66grams total rounded to 52grams. Hope this helps.
If there is 0.492grams of cocoa per 1cm3 and there are 15grams of cocoa in a tablespoon then there will be 15x0.492grams, which means there is 7.38grams of cocoa per 1 tablespoon. Since the recipe uses 7 tablespoons of cocoa(2 for the cake and 5 for the buttercream) then you will need 7.38*7=51.66grams total rounded to 52grams. Hope this helps.