Google-sheets – How to calculate the following mathematical expression in Google Sheets

With a help from a friend, he was able to create the following JavaScript which was imported into Google Sheets' Script Editor and then referenced as =PlanarPolygonAreaMeters2(A1,B1,C1)/1000000

var radiansPerDegree = Math.PI / 180.0;
var degreesPerRadian = 180.0 / Math.PI;
var earthRadiusMeters = 6367460.0;
var metersPerDegree = 2.0 * Math.PI * earthRadiusMeters / 360.0;
var metersPerKm = 1000.0;
var meters2PerHectare = 10000.0;
var feetPerMeter = 3.2808399;
var feetPerMile = 5280.0;
var acresPerMile2 = 640;

function PlanarPolygonAreaMeters2(p1, p2, p3) {
    var points = [p1, p2, p3];
    Utilities.sleep(1500);
    var a = 0.0;
    for (var i = 0; i < points.length; ++i) {
        var j = (i + 1) % points.length;

        var thisPointRaw = points[i];
        var nextPointRaw = points[j];
        var thisPointLat = thisPointRaw.split(/,/)[0];
        var thisPointLng = thisPointRaw.split(/,/)[1];

        var nextPointLat = nextPointRaw.split(/,/)[0];
        var nextPointLng = nextPointRaw.split(/,/)[1];

        var xi = thisPointLng * metersPerDegree * Math.cos(thisPointLat * radiansPerDegree);
        var yi = thisPointLat * metersPerDegree;
        var xj = nextPointLng * metersPerDegree * Math.cos(nextPointLat * radiansPerDegree);
        var yj = nextPointLat * metersPerDegree;
        a += xi * yj - xj * yi;
    }
    return Math.abs(a / 2.0);

}

The raw output of this script is in m².

=sum(arrayformula(A2:A4*C2:C4*(B2:B4="Y")))