Interest charged when you miss a payment is called

Left unresolved, a missed payment might turn into a costly blunder thanks to the combination of a late fee and any interest charged on the balance. Keep in mind that most credit card companies charge interest on a daily basis, so you'll be charged interest for each day you carry a balance.

Iwould say they are complementary because that’s the division of a 90 degree angle and it’s split between the middle of them

Divide 40%5 and your answer is 8