RD Sharma - Mathematics

Book: RD Sharma - Mathematics

Chapter: 20. Surface Area and Volume of a Right Circular Cone

Subject: Mathematics - Class 9th

Q. No. 10 of Exercise 20.1

Listen NCERT Audio Books - Kitabein Ab Bolengi

10

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 π=22/7)

We have,


Let radius of cone = r =4x,


Let slant height = l =7x


Area of curved surface = πrl = 792 cm2


Now, πrl = 792


=


r =4×3= 12 cm


l = 7×3 = 21 cm


Chapter Exercises

More Exercise Questions