Here, h = 77 cm,

Outer radius (R) = 4. 4/ 2 cm = 2.2 cm,

Inner radius (r) = 4/ 2 cm = 2 cm

(i) Inner curved surface area of the pipe

= 2πrh

= 2 × 22/ 7 × 2 × 77 cm^{2}

= 2 × 22 × 22 cm^{2} = **968 cm**^{2 }Ans.

(ii) Outer curved surface area of the pipe = 2πRh

= 2 × 22/ 7 × 2.2 × 77 cm^{2} = 44 × 24.2 cm^{2 }

= 1064.80 cm^{2} Ans.

(iii) Total surface area of the pipe = inner curved surface area + outer

curved surface area + areas of the two base rings.

= 2πrh + 2πRh + 2π (R^{2} – r^{2})

= 968 cm^{2} + 1064.80 cm^{2} + 2 × 22/ 7 [(2.2)^{2} – 22] cm^{2 }

= 2032.80 cm^{2 }+ 5.28 cm^{2} =** 2038.08 cm**^{2} Ans