题目

轴截面是直角三角形的圆锥的底面半径为r，则其轴截面面积为________. 答案：r2 解析:由于圆锥的轴截面是等腰三角形，且顶角为90°，∴S轴截面=·2r·r=r2.—Thank you for helping me order the food.—_________.A．All right.B．Never mind.C．My pleasureD．I’m glad you enjoy it.