is
8.
The length of a roller is 40 cm and its diameter is 21 cm. It takes 300 complete
revolutions to move once over to level the floor of a room. Find the area of the
room in m2.
Answers
Answered by
3
is
8.
The length of a roller is 40 cm and its diameter is 21 cm. It takes 300 complete
revolutions to move once over to level the floor of a room. Find the area of the
room in m2.
Answered by
23
Answer:-
★ Given:-
- Length of roller = 40cm
- Diameter of Roller = 21 cm
- Number of times revolution taken to level the floor of the room = 300
★ To Find:-
- Area of Room in m²
★ Formula Used:-
- Radius = Diameter ÷ 2
- Lateral Surface area of Cylinder = 2 × π × radius × height
★ Concept Used:-
- Area of room = No. of revolution × L.S.A. of Roller
★ Solution:-
➲ Finding Radius of roller
Radius
= Diameter ÷ 2
= 21 ÷ 2
= 10.5 cm
∴ Radius of roller = 10.5 cm
➲ Finding L.S.A. of roller
Lateral Surface area of Cylinder
= 2 × π × radius × height
= 2 × π × 10.5 × 40
= 2 × (22/7) × 10.5 × 40
= 2 × 22 × 1.5 × 40
= 44 × 60
= 2640cm²
∴ L.S.A. of roller = 2640 cm²
➲ Finding area of room
Area of room
= 300 × L.S.A. of Roller
= 300 × 2640
= 792000 cm²
Area of room in m²
= 792000cm²
= 792000 ÷ 10000 [1m² = 10000cm²]
= 79.2 m²
∴ Area of room in m² = 79.2 m²
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