public void TestSurface() { sphere.Radius = 3; Assert.Equal(113.10, sphere.Surface(), 2); sphere.Radius = 77; Assert.Equal(74506.01, sphere.Surface(), 2); sphere.Radius = 6453; Assert.Equal(523278865.12, sphere.Surface(), 2); sphere.Radius = 1; Assert.Equal(12.57, sphere.Surface(), 2); }