Cake, chocolate, prepared from recipe without frosting: piece (1/12 of 9" dia) to Grams
Quick answer
One piece (1/12 of 9" dia) of cake, chocolate, prepared from recipe without frosting weighs 95 grams.
1 piece (1/12 of 9" dia)95 g
Reference serving (nutrition facts)100 g
Source: USDA FoodData Central - SR Legacy (2018-04) (USDA household portion weight)