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# The Radius and Slant Height of a Cone Are in the Ratio of 4 : 7. If Its Curved Surface Area is 792 Cm2, Find Its Radius. (Use It 𝜋 = 22/7). - CBSE Class 9 - Mathematics

ConceptSurface Area of a Right Circular Cone

#### Question

The radius and slant height of a cone are In the ratio of 4 : 7. If its curved surface area is 792 cm2, find its radius. (Use it 𝜋 = 22/7).

#### Solution

Given that,

Curved surface area=pirl=792

Let the radius (r)=4x

Height (h)=7x

Now, CSA=792

22/7xx"4x"xx7x=792

⇒ 88x^2=792

⇒ x^2=792/88=9

⇒ x=3

∴ Radius =4x=4xx3=12cm

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: 10 | Page no. 8
Solution The Radius and Slant Height of a Cone Are in the Ratio of 4 : 7. If Its Curved Surface Area is 792 Cm2, Find Its Radius. (Use It 𝜋 = 22/7). Concept: Surface Area of a Right Circular Cone.
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