"\u7ACB\u4F53\u89D2"@zh . _:b19886 _:b19887 . . . . "\u03C9" . . _:b19887 . _:b19886 . _:b19887 . . . _:b19886 . . _:b19896 . . . . _:b19896 . _:b19896 . _:b19887 . "solid angle"@en . "Solid angle is the ratio of the surface of a portion of a sphere enclosed by the conical surface that forms an angle to the square of the radius of the sphere."@en . . . _:b19886 . . "\u03A9" . "ruimtehoek"@nl . _:b19896 . .