Question

a rectangular strip 15 cm into 3.5 cm is rotated about the longer side find the volume and the whole surface area of the solid that generated​

Answer 1

Step-by-step explanation:

By rotating the strip along longer side, a solid is formed whose radius = 7cm and height = 25 cm

∴ Total surface area =2πr(h+r)

2×227×7(25+7)cm2

44×32=1408cm2

Answer 2

Answer:

area of solid = 407cm²

volume of solid = 577.5cm³

Step-by-step explanation:

On rotating the rectangle along longer side,

a cylinder is formed with radius = 3.5cm and height = 15cm

Total surface area of solid = 2πr(r+h)

= 2×22/7×3.5×(3.5+15)

= 407 cm²

volume of solid = πr²h

=22/7 × 3.5 × 3.5 × 15

= 577.5 cm³