**i) **Height of the pipe = 77 cm

Inner diameter = 4 cm

Inner radius = d/2 = 4/2 = 2 cm

∴ Inner C.S.A. = 2πrh

= 2 × 22/7 × 2 × 77

= 88 × 11 = 968cm^{2}

**ii)** Outer diameter = 4.4 cm

∴ Outer radius, r = d/2 = 4.4/2 = 2.2 cm

∴ Outer C.S.A. = 2πrh

= 2 × 22/7 x 2.2 × 77

= 96.8 × 11

= 1064.8 cm^{2}

**iii)** Total surface area

= Inner C.S.A + Outer C.S.A

= 968 + 1064.8

= 2032.8 cm^{2}