1] A road roller takes 750 complete revolution to move once over to level a road. Find the area of the road if the diameter of the road roller is 84 cm and length is 1 m.
2]The radius and height of a cylinder are in the ratio 5:7 and its volume is 550 cm?. Find the radius and surface area of the cylinder?
PLEASE ANSWER THESE QUESTIONS
I WILL MARK YOU AS BRAINLIEST
Answers
Answer:
(A=750×Area covered in one revolution).
Complete step-by-step answer:
Given that,
Length of roller = h = 1m
Diameter of the roller = 84 cm
Therefore, Radius of the roller = r=842=42 cm
Radius of the roller = 42100 m
Also, given that the roller takes 750 complete revolutions to level the whole road.
Therefore, the area of road = 750 (Area covered in one revolution)
The area of road = 750 (Lateral surface area of cylinder)
The area of road = 750×2πrh
The area of road = 750×2×227×42100×1=750×2×22×6100
The area of road = 1500×132100=15×132=1980
Hence, the area of the road is 1980m2.
2) Let height and radius be
= 7x and 5x respectively
⇒πr2h=550
π(5x)2×7x=550
227×25x2×7x=550
x3=1
x=1
∴Height=7cm
Radius=5cm
⇒ Curved surface area =2πrh
=2×227×5×7=220cm2
Ans = 1} Also, given that the roller takes 750 complete revolutions to level the whole road. Hence, the area of the road is 1980m2.
Ans = 2} The radius and height of a cylinder are in the ratio 5:7 and its volume is 550 cm3. Find its radius. Let radius (r) = 5x and height (h) = 7x. ∴ The required radius = 5x = 5 x 1 = 5cm.
Step-by-step explanation:
Ans = 1} Area of road =750× area covered in 1 revoluation
=750× lateral surface area of cylinder
=750×2πrh
Given, d=84cm⇒r=42cm→ 100/42 m
=750×2× 22/7 × 42 / 100 × 1
= 1500×132
------------------
100
=1980m²
I know only first step - by step explanation
don't know second step - by step explanation