Flutter Trilateration (x,y)

Question

I am trying to make an indoor positioning application for a room. I have 3 ibeacons. In the code below, I get rssi values from these beacons. I tried to find x and y values using them. I tried some formulas but it did not show the x and y coordinates correctly. How do I use the Trilateration Method in my code?

My code:

class TabScanning extends StatefulWidget {
  TabScanning({super.key});

  double x = 0, y = 0;
  @override
  _TabScanningState createState() => _TabScanningState();

}

class _TabScanningState extends State<TabScanning> {
  StreamSubscription<RangingResult>? _streamRanging;
  final _regionBeacons = <Region, List<Beacon>>{};
  final _beacons = <Beacon>[];
  final controller = Get.find<RequirementStateController>();


  double x1 = 0, y1 = 150;
  double x2 = -150, y2 = -150;
  double x3 = 150, y3 = -150;

  double d1 = 0, d2 = 0, d3 = 0;
  int rssi = 0;
  int txPower = -67;
  int N = 2;
  List<double> distance = [0.0, 0.0, 0.0];

  List<Beacon> defaultBeacons = [
    const Beacon(
      proximityUUID: '1AA10000-0A46-215F-E97E-5A966A7DEDC3',
      major: 1,
      minor: 3,
      accuracy: 0.0,
      macAddress: "",
      txPower: 0,
    ),
    const Beacon(
      proximityUUID: '1AA10000-0A46-215F-E97E-5A966A7DEDC3',
      major: 1,
      minor: 4,
      accuracy: 0.0,
      macAddress: "ss",
      txPower: 0,
    ),
    const Beacon(
      proximityUUID: '1AA10000-0A46-215F-E97E-5A966A7DEDC3',
      major: 1,
      minor: 8,
      accuracy: 0.0,
      macAddress: "",
      txPower: 0,
    ),
  ];

  @override
  void initState() {
    super.initState();

    _beacons.addAll(defaultBeacons);

    controller.startStream.listen((flag) {
      if (flag == true) {
        initScanBeacon();
      }
    });

    controller.pauseStream.listen((flag) {
      if (flag == true) {
        //pauseScanBeacon();
      }
    });

  }

  initScanBeacon() async {
    await flutterBeacon.initializeScanning;
    if (!controller.authorizationStatusOk ||
        !controller.locationServiceEnabled ||
        !controller.bluetoothEnabled) {
      print(
          'RETURNED, authorizationStatusOk=${controller.authorizationStatusOk}, '
          'locationServiceEnabled=${controller.locationServiceEnabled}, '
          'bluetoothEnabled=${controller.bluetoothEnabled}');
      return;
    }

    final regions = <Region>[
      Region(
        identifier: 'ibeacon',
        proximityUUID: '1AA10000-0A46-215F-E97E-5A966A7DEDC3',
      ),
    ];

    if (_streamRanging != null) {
      if (_streamRanging!.isPaused) {
        _streamRanging?.resume();
        return;
      }
    }

    _streamRanging =
        flutterBeacon.ranging(regions).listen((RangingResult result) {
      print(result);
      if (mounted) {
        setState(() {
          _regionBeacons[result.region] = result.beacons;


          _beacons.forEach((existingBeacon) {
            result.beacons.forEach((newBeacon) {
              if (existingBeacon.major == newBeacon.major &&
                  existingBeacon.minor == newBeacon.minor) {            
                _beacons[_beacons.indexOf(existingBeacon)] = Beacon(
                  proximityUUID: existingBeacon.proximityUUID,
                  major: existingBeacon.major,
                  minor: existingBeacon.minor,
                  accuracy: newBeacon.accuracy,
                  rssi: newBeacon.rssi,
                  macAddress: newBeacon.macAddress,
                  txPower: newBeacon.txPower,
                );
              }
            });
          });
          _beacons.sort(_compareParameters);


         for (int i = 0; i < _beacons.length; i++) {
            rssi =_beacons[i].rssi;


            if (_beacons[i].minor == 3) {
              dist[0] = pow(10, ((txPower - rssi) / (10 * 2))) as double;
            } else if (_beacons[i].minor == 4) {
              dist[1] = pow(10, ((txPower - rssi) / (10 * 2))) as double;
            } else if (_beacons[i].minor == 8) {
              dist[2] = pow(10, ((txPower - rssi) / (10 * 2))) as double;
            }
          }

            d1 = dist[0];
            d2 = dist[1];
            d3 = dist[2];


            double a = (-2 * x1) + (2 * x2);
            double b = (-2 * y1) + (2 * y2);
            num c = pow(d1, 2) -
                pow(d2, 2) -
                pow(x1, 2) +
                pow(x2, 2) -
                pow(y1, 2) +
                pow(y2, 2);
            double d = (-2 * x2) + (2 * x3);
            double e = (-2 * y2) + (2 * y3);
            num f = pow(d2, 2) -
                pow(d3, 2) -
                pow(x2, 2) +
                pow(x3, 2) -
                pow(y2, 2) +
                pow(y3, 2);

            widget.x = (c * e - f * b);
            widget.x = widget.x / (e * a - b * d);

            widget.y = (c * d - a * f);
            widget.y = widget.y / (b * d - a * e);

        });
      }
    });
  }


  pauseScanBeacon() async {
    //_streamRanging?.pause();
    if (_beacons.isNotEmpty) {
      setState(() {
        //_beacons.clear();
      });
    }
  }

  int _compareParameters(Beacon a, Beacon b) {
    int compare = a.proximityUUID.compareTo(b.proximityUUID);
    if (compare == 0) {compare = a.major.compareTo(b.major);}
    if (compare == 0) {compare = a.minor.compareTo(b.minor);}
    return compare;
  }
}

I found this calculation on github. But it only shows numbers like x= 0.012........ y= -38.15........ it doesn't change much.

my app myapp2