Multiply number with Pi in solidity

Question

I'm finding a library to implement this formula in solidity.

Is there is a library to implement this formula.

Answer 1

Use PRBMath!

// SPDX-License-Identifier: Unlicense
pragma solidity >=0.8.4;
import "prb-math/contracts/PRBMathSD59x18.sol";
contract SignedConsumer {
  using PRBMathSD59x18 for int256;
/// @notice Calculates x*PI÷1e18 while handling possible intermediary overflow.  function multiplyByPi(int256 x) external pure returns (int256 result) {
    int256 pi = PRBMathSD59x18.pi();
    result = x.mul(pi);
  }
}

P.S. see my comparison of fixed-point math libraries for Solidity: What fixed or float point math libraries are available in solidity?