Advertisements
Advertisements
प्रश्न
The slant height of a frustum of a cone is 4 m and the perimeter of circular ends is 18 m and 16 m. Find the cost of painting its curved surface area at ₹ 100 per sq. m
Advertisements
उत्तर
Slant height of a frustum (l) = 4 m
Perimeter of the top part = 18 m
2πR = 18
`2 xx 22/7 xx "R"` = 18
R = `(18 xx 7)/(2 xx 22) xx 63/22`
Perimeter of the bottom = 16 m
2πr = 16
`2 xx 22/7 xx "r"` = 16
r = `(16 xx 7)/(2 xx 22) = 28/11`
C.S.A of the frustum = π l (R + r) sq.units
= `22/7 xx 4 (63/22 + 28/11)`
= `22/7 xx 4 ((63 + 56)/22)`
= `22/7 xx 4 xx 119/22`
= 4 × 17
= 68 sq.units
Cost of painting
= ₹ 100 × 68
= ₹ 6800
APPEARS IN
संबंधित प्रश्न
A metal container, open from the top, is in the shape of a frustum of a cone of height 21 cm with radii of its lower and upper circular ends as 8 cm and 20 cm respectively. Find the cost of milk which can completely fill the container at the rate of Rs 35 per litre.\[\left[ Use \pi = \frac{22}{7} \right]\]
A metallic bucket, open at the top, of height 24 cm is in the form of the frustum of a cone, the radii of whose lower and upper circular ends are 7 cm and 14 cm respectively. Find :
(i) the volume of water which can completely fill the bucket.
(ii) the area of the metal sheet used to make the bucket.
[Use π =\[\frac{22}{7}\]
The radii of the ends of a frustum are 14 cm and 6 cm respectively and its height is 6 cm. Find its curved surface area.
An oil funnel of tin sheet consists of a cylindrical portion 10 cm long attached to a frustum of a cone. If the total height be 22 cm, the diameter of the cylindrical portion 8 cm and the diameter of the top of the funnel 18 cm, find the area of the tin required.(Use π = 22/7).
The diameters of the ends of a frustum of a cone are 32 cm and 20 cm. If its slant height is 10 cm, then its lateral surface area is
A cone of height 20 cm and radius of base 5 cm is made up of modelling clay. A child reshapes it in the form of a sphere. Find the diameter of the sphere.
A shuttle cock used for playing badminton has the shape of a combination of ______.
A cylinder and a cone area of same base radius and of same height. The ratio of the volume of cylinder to that of cone is ______.
The diameters of the two circular ends of the bucket are 44 cm and 24 cm. The height of the bucket is 35 cm. The capacity of the bucket is ______.
Find the curved surface area of a right circular cone whose height is 15 cm and base radius is 8 cm. tan β = `3/4`.
