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 π = \(\frac{22}{7}\))
- 2.1 m\(^2\)
- 3.5 m\(^2\)
-
4.0 m\(^2\)
- 9.4 m\(^2\)
The correct answer is: C
Explanation
The total surface area A of a closed cylindrical barrel (closed at one end), is given by:
A = πr\(^2\) + 2πrh = πr(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\(^2\)