The volume formulas needed are:
Cylinder: V=πr2h
Cone: V=31πr2h
Sphere: V=34πr3
For the cylinder with radius r=7 cm and height h=10 cm:
VA=πr2h
VA=π×(7)2×10
VA=π×49×10
VA=490π cm³
For the cone with radius r=7 cm and height h=9 cm:
VB=31πr2h
VB=31×π×(7)2×9
VB=31×π×49×9
VB=31×π×441
VB=147π cm³
For the sphere with radius r=6 cm:
VC=34πr3
VC=34×π×(6)3
VC=34×π×216
VC=3864×π
VC=288π cm³
Comparing the volumes:
Cylinder (A): 490π cm³
Sphere (C): 288π cm³
Cone (B): 147π cm³
The decreasing order is: (A), (C), (B)