The diameters of two cones are equal. If their slant heights are in the ratio 5:4, find the ratio of their curved surface areas. - Noon Academy

The diameters of two cones are equal. If their slant heights are in the ratio 5:4, find the ratio of their curved surface areas.

Class 10 | Cylinder, Cone and Sphere (Surface Area and Volume) | Exercise 20B | ICSE | Selina

The diameters of two cones are equal. If their slant heights are in the ratio 5:4, find the ratio of their curved surface areas.

Let radius of each cone = r

Given that, ratio between their slant heights = 5: 4

Let slant height of the first cone = 5x

And slant height of second cone = 4x

So, curved surface area of the first cone = πrl = πr x (5x) = 5πrx

And, the curved surface area of the second cone = πr x (4x) = 4πrx

The ratio between them = 5πrx: 4πrx = 5: 4

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