The volume of the conical part is equal to the volume of the rising part after the water in the cylindrical glass tank is 20/2= 10 cm.

10x10x3.14x6 =1884 (cubic centimeter)

So the volume of the conical part is 1884 cubic centimeters.

(2) Because several girls were transferred later, the ratio of boys to girls was 6:5. At this time, * * * has 880 students, 880X5/ 1 1=400 (people).

880-400=480 (person)

So there are 480 boys and 400 girls, so there are 450 girls. 450-400=50.

Move 50 girls.

(3) 1080÷(40%+50%)

= 1080÷0.9

= 1200 (yuan)

So the original price of these two boots is 1200 yuan per pair.