A solid metallic rectangular block of dimensions 112 cm × 44 cm × 25 cm is melted and recast into a cylinder of radius 35 cm. The curved surface area (in cm2) of the cylinder is: (Take π=22/7)
Options
a) 7260
b) 6600
c) 7040
d) 6160
Solutions
As per questions
Volume of cuboid = $ \L \times B \times H$
Volume of cylinder = $ \pi r^2h$
Curved surface area of the cylinder = $ 2\pi rh$
L = 112
B = 44
H = 25
R = 35
H = ?
H = 112 x 44 x 25 = $ \frac{22}{7} \times 35 \times 35$
H = 112 x 44 x 25 x 7 = 22 x 35 x 35
H = 32
Curved surface area of the cylinder = $ 2 \pi rh$
= $ 2 \times \frac{22}{7} \times 35\times 32$
= 44 x 160
= 7040
Ans: c) 7040