Ethereum contract size limit for multipage contract

Question

I got to know that there is a size limitation for Ethereum contract, but to avoid this I split up functions of my contract in two sol files and one contract extends other contract and this solve the size limit problem but I just want to confirm is I am doing anything wrong or I am missing anything?

For example
Previously
File A.sol
Contract A {
function f1(){}
function f2(){}
function f3(){}
function f4(){}
}
Now
A.sol
import "./B.sol"
contract A is B{
function f3() public {}
function f4() public {}
}
B.sol
contract B{
function f2(){}
function f3(){}
}

Answer 1

One contract extends other contract, and this solve the size-limit problem

That's wrong.

When B inherits A, the entire contents of A is included in B.

What you want is for B to take the address of (an instance of) A as input, either in the constructor of B, or in every function of B which needs to call a function of A.

Then, every function of B which needs to call a function of A, should call it via the address of A.