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The Diameters of Two Cones Are Equal. If Their Slant Heights Are in the Ratio 5 : 4, Find the Ratio Of Their Curved Surfaces. - CBSE Class 9 - Mathematics

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Question

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

Solution

Given that,
Diameters of two cones are equal 

∴ Their radius are also equal i.e., `r_1=r_2` 

Let the ratio of slant height be x 

∴` l_1=5x and l_2=4x`

∴ Ratio of curved surface area =`C_1/C_2` 

∴ `C_1/C_2=(pir_1l_1)/(pir_2l_2)=(pir_1sx)/(pir_2(4x)=)5/4` 

∴ Ratio of curved surface area = 5:4

  Is there an error in this question or solution?

APPEARS IN

 RD Sharma Solution for Mathematics for Class 9 by R D Sharma (2018-19 Session) (2018 to Current)
Chapter 20: Surface Areas and Volume of A Right Circular Cone
Ex.20.10 | Q: 14 | Page no. 8
Solution The Diameters of Two Cones Are Equal. If Their Slant Heights Are in the Ratio 5 : 4, Find the Ratio Of Their Curved Surfaces. Concept: Surface Area of a Right Circular Cone.
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