A piece of hard paper of right triangle with two right sides of 5cm and 8cm respectively. The volume of three-dimensional figure can be obtained by rotating one right side of it as an axis The biggest is

A piece of hard paper of right triangle with two right sides of 5cm and 8cm respectively. The volume of three-dimensional figure can be obtained by rotating one right side of it as an axis The biggest is

It can be divided into two cases: ① with the right angle side = 8 cm as the axis, the volume V1 = 1 / 3 π × 5 & # 178; × 8 = 200 / 3 π CM & # 179; ② with the right angle side = 5 cm as the axis, the volume V2 = 1 / 3 π × 8 & # 178; × 5 = 320 / 3 π CM & # 179;, and then the comparison shows that V2 > V