E3-21 (similar to) Fill in the blanks for each of the following independent cases (Click the icon to view the cases.) (For entries with a $0 balance, make sure to enter "0" in the appropriate cell, Round the contribution margin percentage to the nearest whole percent) Variable Fixed Total Operating Contribution Revenuers Costs Costs Coests ncomeMargin Percentsge Case 87 % a. S 2.300 $ 300 S 500 S 800 S 1,500 b. s 2,500 S 500 E3-21 (similar to) Fill in the blanks for each of the following independent cases (Click the icon to view the cases.) (For entries with a $0 balance, make sure to enter "0" in the appropriate cell, Round the contribution margin percentage to the nearest whole percent) Variable Fixed Total Operating Contribution Revenuers Costs Costs Coests ncomeMargin Percentsge Case 87 % a. S 2.300 $ 300 S 500 S 800 S 1,500 b. s 2,500 S 500