an iron pipe 20cm long has external diameter equal to 25 CM if the thickness of the pipe is 1 centimetre find the whole surface of the pipe
and the correct answer is 3168cm^2
Answers
Step-by-step explanation:
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
So, the total surface area of the pipe is 3168 square cm
Answer:
3168 cm²
Step-by-step explanation:
Length of iron pipe(h) = 20 cm.
External Diameter = 25 cm,
then external radius will be R = 25/2 = 12.5 cm.
Thickness of pipe = 1 cm.
Internal diameter = 25 - (1 + 1) = 25 - 2 = 23 cm
then internal radius will be r = 23/2 = 11.5 cm.
Total surface area of pipe = External C.S.A + Internal C.S.A + 2(Base area)
=> 2πRh + 2πrh + 2π(R² - r²)
=> 2πh(R + r) + 2π(R² - r²)
=> 2 * 22/7 * 20 * (12.5 + 11.5) + 2 * (22/7) * (12.5² - 11.5²)
=> 2 * 22/7 * 20 * 24 + 2 * 22/7 * 24
=> 2 * 22/7 * 24(20 + 1)
=> 2 * 22/7 * 24(21)
=> 2 * 22 * 24 * 3
=> 3168 cm²
Therefore, whole surface area of pipe = 3168 cm²
Hope it helps!