Surface Areas and Volumes Test - 6

Given,

The circumference of the base of a right circular cylinder = 44 cm

2πr = 44

r = 44 × 7/(22×2)

r = 7 cm

whole surface area= 2πrh + 2πr²

968 = 2 × 22/7 × 7(h+r)

h + r = 22 cm

the circumference of its base = 110 cm

2πr=110

r=35/2

CSA=4400 cm²

2πrh=4400

h=4400/2πr

   =4400/110

   =40 cm

So here, radius would be half of edge of cube, or diameter of rod=edge of cube

r=2 cm

h=4 cm

so, volume= πr²h

                 =π × 2×2×4

                 =16π cm³

Number of bags= Volume of drum/ volume of one bag

 =2πrh/2.1

 =(2×22/7×4.2×3.5)/2.1

 =92

volume of reduced cylinder : volume of original cylinder

π(r/2)²h : πr²h

1: 4

CSA of original cylinder =2πrh

CSA of new cylinder= 2×π×r/2×2h

                                =2πrh

volume of cylinder1 : volume of cylinder2

= π×(2r)² × 5h : π×(3r)² ×3h

= 20:27

since, diameter is 42 cm

radius would be 21 cm

Volume of sphere = 4/3×π×r³

                                  ^{=4/3 × 22/7 × (21)³}

                            =38808 cm³

Given r= 3.5 cm

Surface area of sphere= 4πr²

                                     =4 × 22/7 × 3.5 × 3.5

                                     =154 cm²

Volume of sphere= surface area of sphere

4/3πr³= 4πr²

r= 3 units

so, diameter= 6 units