A rectangular piece of length 12 cm and breadth 4 cm is folded to form a cylinder. Find its curved surface area.

Correct Answer - (i) `432 cm^(3), 180 cm^(2), 372 cm^(2)` (ii) `2366 m^(3), 520m^(2), 1248 m^(2)` (iii) `45 m^(3), 21 m^(2), 201 m^(2)` (iv) `36m^(3), 291 m^(2), 303 m^(2)`

Correct Answer - (i) 1m (ii) `1.54 m^(3)`

Correct Answer - `269.5 cm^(3)`

Correct Answer - `1078 cm^(3)`

Correct option is  A) 7

Correct option is (C) 48 cm2 \(\therefore\) Curved surface area of formed cylinder = Area of rectangular sheet = 12 \(\times\) 4 \(=48\,cm^2\)

Correct option is (D) 7 Let radius of cylinder be r cm. \(\therefore\) Circumference of base of cylinder = Length of rectangle \(\therefore\) \(2\pi r=44\) \(\Rightarrow\) \(r=\frac{44}{2\pi}=\frac{44\times7}{2\times22}\) = 7 \(\therefore\) Radius of the cylinder is 7 cm.

Correct option is (B) 2π xy cm2 r = x cm & h = y cm \(\therefore\) Curved surface area of cylinder \(=2\pi rh\) = \(2\pi\,xy\,cm^2\)