Question

PLEASE SOLVE THE ANSWER OF THE ABOVE QUESTION..

CHAPTER-13: surface areas and volumes. (NCERT)

CLASS-9​

Answer 1

Internal radius = r = 4/2 cm = 2 cm

External radius = R = 4.4/2 cm = 2.2 cm

Length of the pipe = h = 77 cm

(i) Inner curved surface area = 2πrh = 2 x 22/7 x 2 x 77 cm2 = 968 cm2

(ii) Outer curved surface area = 2πRh = 2 x 22/7 x 2.2 x 77 cm2 = 1064.8 cm2

(iii) Total surface area of pipe = Inner curved surface area + Outer curved surface area + Surface area of the ends

∴ Total surface area of pipe = 2πrh + 2πRh + 2π(R2 - r2)

= 2 x 22/7 x 2 x 77 + 2 x 22/7 x 2.2 x 77 + 2 x 22/7(2.2 2 - 22)

= 968 cm2 + 1064.8 cm2 + 5.28 cm2 = 2038.08 cm2

Answer 2

Answer:

hope it helps..................