Advertisements
Advertisements
Question
The base circumferences of two cones are the same. If their slant heights are in the ratio 5 : 4, find the ratio of their curved surface areas.
Solution
The base circumferences of the cones are equal, therefore the radius of base are equal.
Let radius be r.
Ratio between slant heights= 5:4
Let slant height of first cone = 5x and of second cone = 4x
Curved surface area of cone = `pirl` (where l = slant height)
Ratio of curved surface areas = `(pir xx 5x)/(pir xx 4x)`
= `5/4`
Ratio of curved surface areas = 5:4
APPEARS IN
RELATED QUESTIONS
In Figure, find the area of the shaded region [Use π = 3.14]
A sheet of paper is in the form of rectangle ABCD in which AB = 40cm and AD = 28 cm. A semicircular portion with BC as diameter is cut off. Find the area of remaining paper.
The side of a square is 10 cm. find the area of circumscribed and inscribed circles.
Find the angle subtended at the centre of circle of radius 5cm by an arc of length `((5pi)/3)` cm
Find the angle subtended at the centre of circle of radius ‘a’ cm by an arc of length
`(api)/4` 𝑐𝑚
A playground has the shape of rectangle, with two semicircles on its smaller sides as diameters, added to its outside. If the sides of rectangle are 36m and 24.5m. find the area of playground.
Find the circumferences of a circle whose radius is 7 cm.
Find the area of a quadrant of a circle whose circumference is 44 cm.
A wire when bent in the form of an equilateral triangle encloses an area of `121sqrt(3) "cm"^2`. The same wire is bent to form a circle. Find the area enclosed by the circle.
In a circle of radius 10.5 cm, the minor arc is one-fifth of the major arc. Find the area of the sector corresponding to the major arc.
The inside perimeter of a running track shown in the figure is 400 m. The length of each of the straight portions is 90 m, and the ends are semicircles. If the track is 14 m wide everywhere, find the area of the track. Also, find the length of the outer boundary of the track.
The areas of two circles are in the ratio 9 : 4. The ratio of their circumferences is
Find the volume and the surface area of the spheres in the following :
Diameter= 6.3 cm
A cylindrical bucket, whose base radius is 20 cm, is filled with water to a height of 25 cm. A heavy iron spherical ball of radius 10 cm is dropped to submerge completely in water in the bucket. Find the increase in the level of water.
Find the diameter of the sphere for the following :
Volume = `523 17/21` cm3
Find the diameter of a circle whose circumference is equal to the sum of circumference of circles with radius 10 cm, 12 cm, and 18 cm.
The diameter of two circles are 28 cm and 24 cm. Find the circumference of the circle having its area equal to sum of the areas of the two circles.
A cart wheel makes 9 revolutions per second. If the diameter of the wheel is 42cm, find its speed in km per hour. (Answer correct to the nearest km)
The radius of a circular plot is 7.7 metres. How much will it cost to fence the plot with 3 rounds of wire at the rate of 50 rupees per metre?
In covering a distance s metres, a circular wheel of radius r metres makes `s/(2πr)` revolutions. Is this statement true? Why?
