A cylindrical metallic barrel of height 2.5m and radius 0.245 is closed at one end. Find, correct to one decimal place, the total surface area of the barrel (Take \pi = \(\frac{22}{7}\))
A
2.1 m\(^2\)
B
3.5 m\(^2\)
C
4.0 m\(^2\)
D
9.4 m\(^2\)
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
The total surface area A of a closed cylindrical barrel (closed at one end), is given by:
A = \pir\(^2\) + 2\pirh = \pir(r + 2h)
BUT, r = 0.245m, h = 2.5m
A = \(\frac{22}{7}\) x 0.245( 0.245 + 2 x 2.5)
A = 0.77(5.245) = 4.038650m\(^2\) ≈ 4.0m\(^2\)
Source: Myschool Past Questions Archive (Record #71776)