在正方体中,三棱锥的表面积为,则正方体外接球的体积为( )A. B. C. D. 答案:【答案】B【解析】根据三棱锥的表面积进一步求出正方体的棱长,最后求出正方体的外接球的半径,进一步求出结果.解:设正方体的棱长为,则,由于三棱锥的表面积为,所以所以所以正方体的外接球的半径为,所以正方体的外接球的体积为故选:. — I am afraid the task is too difficult for me, sir. —___________, Linda. Just believe in yourself! A. No problem B. That's all right C. That's OK D. Come on