Question

The diameter of roller is 2.5m and its length is 1.4m . How much area will it cover in 7 revolutions ? ​

Answer 1

Answer:

Radius of the roller (cylinder) =  

Length of the roller = 1.4m

Curved surface area of the roller = 2πrh

= 2 ×  ×  × 1.4

= 11 m²

We know that,

Area covered in one revolution = Curved surface area

Therefore,

Area covered in 7 revolution = 7 × Curved surface area

= 7 × 11 = 77 m²

Hence, the roller will cover 77m² in 7 revolution.

Step-by-step explanation:

Answer 2

$radius \: of \: the \: roller \: (cylinder) = \frac{2.5}{2 } \\ length \: of \: the \: roller \: = 1.4m \: \\ curved \: surface \: area \: of \: the \: roller \: = 2\pi rh \\ = > 2 \times \frac{22}{7} \times \frac{2.5}{2} \times 1.4 \\ = > 11 {m}^{2}$

We know that ,

Area covered in one revolution = curved surface area

Therefore ,

Area covered in 7 revolution = 7 × curved surface area

$= > 7 \times 11 = 77 {m}^{2}$