Advertisements
Advertisements
Question
A roller has a diameter of 1.4 m. Find :
(i) its circumference ;
(ii) the number of revolutions it makes while travelling 61.6 m.
Advertisements
Solution
Diameter = 1.4 m
r = `1.4/2 = 0.7` m
∴ Circumference of roller = `2pir`
= `2 xx 22/7 xx 0.7 = 4.4` m
Revolutions made in 4.4 m distance = 1
Revolutions made in 1 m distance = `1/4.4`
Revolutions made in 61.6 m distance
= `1/4.4 xx 61.6 = 616/44 = 14`
Hence (i) 4.4 m (ii) 14
APPEARS IN
RELATED QUESTIONS
A path of width 3.5 m runs around a semi-circular grassy plot whose perimeter is 72 m . Find the area of the path .
`("Use" pi= 22/7) `
Find the area of the following figure, in square cm, correct to one place of decimal. (Take π = 22/7).
In the following figure, there are three semicircles, A, B and C having diameter 3 cm each, and another semicircle E having a circle D with diameter 4.5 cm are shown. Calculate:
(i) the area of the shaded region
(ii) the cost of painting the shaded region at the rate of 25 paise per cm2 , to the nearest rupee.
In the following figure, ABC is a right-angled triangle, ∠B = 90°, AB = 28 cm and BC = 21 cm. With AC as diameter a semicircle is drawn and with BC as radius a quarter circle is drawn. Find the area of the shaded region correct to two decimal places.
If the numerical value of the area of a circle is equal to the numerical value of its circumference , find its radius.
The area of the largest triangle that can be inscribed in a semi-circle of radius r is
Area of the largest triangle that can be inscribed in a semi-circle of radius r units is ______.
The length of an arc of a circle, subtending an angle of 54° at the centre is 16.5 cm. Calculate the radius, circumference and area of the circle.
In the given figure, PQ = 24 cm, PR = 7 cm and O is the centre of the circle. Find the area of the shaded region. [Take π = 3.14.]
The diameters of three wheels are in the ratio 2 : 4 : 8. If the sum of the circumferences of these circles be 132 cm, find the difference between the areas of the largest and the smallest of these wheels.
