已知在△ABC中,∠C=90°,AB=12,点G为△ABC的重心,那么CG=____.
—I don't know. I have to look it up in the dictionary,
Why doesn't the woman choose the black dress?
已知地球半径为R,质量为M,万有引力常量为G.一位质量为m的探险家乘坐热气球到达离地面h高处,他受到地球的万有引力大小为( )
根据幂的意义,(-3)4表示____,-43表示____;