Question

find the Surface area of a
hollow cylinder of internal Radius
3cm width 0.5cm and height 7cm​

Answer 1

Step-by-step explanation:

Given internal radius r=3 cm

External radius R=(3+1) cm (Since thickness is 1 cm)

∴ Total surface area =2π(R+r)(h+R−r)

==2×722×(4+3)(14+4−3)=744×7×15=660cm2