Question

What are the kinds of formulas to remember in 8th grade?

Answer 1

you should better know formula of circumference and areas of circle. rectangle . triangle etc also for speed,  velocity ... also some important conversions... 

Answer 2

The best formulas to remember from the 8th grade are the ones
that have been introduced in 8th grade math class, and which have
been used to solve the math homework assigned in 8th grade.
This sneaky trick works every time, and most kids never think of it..