Question

the external diameter of an iron pipe is 25 cm and its length is 20 CM if the thickness of the pipe is 1 cm find the total surface area of the pipe​

Answer 1

≡QUESTION≡

The external diameter of an iron pipe is 25 cm and its length is 20 cm. If the thickness of the pipe is 1 cm, find the total surface area of the pipe​.

                                                                                   

║⊕ANSWER⊕║

GIVEN

Height of pipe = 20 cm

External diameter = 25 cm 

External radius = 25/2

                           = 12.5 cm

Internal diameter = 25 - (1 + 1)

                               = 23 cm

Internal radius = 23/2 = 11.5 cm

Let the external radius be R and the internal radius be r.

Total surface area of the pipe = 2πh(R + r) + 2π(R² - r²)

⇒ 2*22/7*20(12.5 + 11.5) + 2*22/7*{(12.5)² - (11.5²)

⇒ (44*480)/7 + (44*24)/7

⇒ 21120/7 + 1056/7

⇒ 22176/7

= 3168 cm²

∴The total surface area of the pipe is 3168 square cm.