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
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
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.
If r1 and r2 denote the radii of the circular bases of the frustum of a cone such that r1 > r2, then write the ratio of the height of the cone of which the frustum is a part to the height fo the frustum.
If the slant height of the frustum of a cone is 6 cm and the perimeters of its circular bases are 24 cm and 12 cm respectively. What is the curved surface area of the frustum?
A metallic sphere of radius 10.5 cm is melted and then recast into small cones, each of radius 3.5 cm and height 3 cm. The number of such cones is
The material of a cone is converted into the shape of a cylinder of equal radius. If height of the cylinder is 5 cm, then height of the cone is
A cylinder with base radius of 8 cm and height of 2 cm is melted to form a cone of height 6 cm. The radius of the cone is
A solid metallic sphere of diameter 28 cm is melted and recast into a number of smaller cones, each of diameter `"4"2/3` cm and height 3 cm. Find the number of cones so formed.
An oil funnel of the tin sheet consists of a cylindrical portion 10 cm long attached to a frustum of a cone. If the total height is 22 cm, the diameter of the cylindrical portion by 8 cm and the diameter of the top of the funnel be 18 cm, then find the area of the tin sheet required to make the funnel.
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 ______.
An open metallic bucket is in the shape of a frustum of a cone, mounted on a hollow cylindrical base made of the same metallic sheet. The surface area of the metallic sheet used is equal to curved surface area of frustum of a cone + area of circular base + curved surface area of cylinder.
