关于c＃：凸四边形区域的数值精度

Numerical precision of implementation for convex quadrilateral area

我已经实现了一种计算r3中凸四边形面积的方法。这个方法很好用，但我在小数点后8位遇到了数值精度问题。看看这个方法：

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internal static double GetTriangleArea(double ax, double ay, double az,
double bx, double by, double bz,
double cx, double cy, double cz
)
{
/**
* AB = B-A = (ux, uy, uz)
* AC = C-A = (wx, wy, wz)
*
* S = 0.5*sqrt{(uy*wz - uz*wy)2 + (uz*wx - ux*wz)2 + (ux*wy - uy*wx)2}
* */

var ux = bx - ax;
var uy = by - ay;
var uz = bz - az;

var wx = cx - ax;
var wy = cy - ay;
var wz = cz - az;

var t1 = uy*wz - uz*wy;
var t2 = uz*wx - ux*wz;
var t3 = ux*wy - uy*wx;
var s = 0.5*Math.Sqrt(t1*t1 + t2*t2 + t3*t3);

return s;
}

internal static double GetConvexQuadrilateralArea(double ax, double ay, double az,
double bx, double by, double bz,
double cx, double cy, double cz,
double dx, double dy, double dz)
{
var triangle1 = GetTriangleArea(ax, ay, az, bx, by, bz, cx, cy, cz);
var triangle2 = GetTriangleArea(ax, ay, az, cx, cy, cz, dx,dy,dz);

return triangle1 + triangle2;
}

这就是测试：

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[TestMethod]
public void ParallelogramOfBaseBAndHeightHMustHaveAreaEqualToBTimesH()
{
var random = new Random(1);
const double scale = 10000;
for (var counter = 0; counter < 1000; counter++)
{
double baseLength = random.NextDouble() * scale;
double height = random.NextDouble() * scale;

double dx = random.NextDouble()*scale;

var a = new[] { 0, 0, 0 };
var b = new[] { baseLength, 0, 0 };
var c = new[] { baseLength+dx, height, 0 };
var d = new[] { 0F+dx, height, 0 };

double expected = baseLength * height;

var result = MathUtils.GetConvexQuadrilateralArea(a[0], a[1], a[2], b[0], b[1], b[2], c[0], c[1], c[2],
d[0], d[1], d[2]);

Assert.AreEqual(expected, result, Epsilon*scale,
string.Format("sideA: {0}, height: {1}, dx: {2}", baseLength, height, dx));
}
}

此测试失败，并显示以下消息：预期值74813926.2967871和实际值74813926.2967871之间的差异不大于<1e-09>。侧：8552.44307245707，高：8747.66726454146，深：4721.64729829954。

我的问题是：在仍然使用双精度数字的情况下，有没有办法提高实现的数字精度？