# Chapter 13 – Surface Areas and Volumes Questions and Answers: NCERT Solutions for Class 10 Maths

Class 10 Maths NCERT book solutions for Chapter 13 - Surface Areas and Volumes Questions and Answers.

= π cm3

## 5. An oil funnel made of tin sheet consists of a 10 cm long cylindrical portion attached to a frustum of a cone. If the total height is 22 cm, diameter of the cylindrical portion is 8 cm and the diameter of the top of the funnel is 18 cm, find the area of the tin sheet required to make the funnel (see Fig.).

### Solution: Given, Diameter of upper circular end of frustum part = 18 cm So, radius (r1) = 9 cm Now, the radius of the lower circular end of frustum (r2) will be equal to the radius of the circular end of the cylinder So, r2= 8/2 = 4 cm Now, height (h1) of the frustum section = 22 – 10 = 12 cm And, Height (h2) of cylindrical section = 10 cm (given) Now, the slant height will be-

Or, l = 13 cm
Area of tin sheet required = CSA of frustum part + CSA of cylindrical part
= π(r1+r2)l+2πr2h2
Solving this we get,
Area of tin sheet required = 782 4/7 cm2