from a handpicked tutor in LIVE 1-to-1 classes

# The slant height and base diameter of a conical tomb are 25 m and 14 m respectively. Find the cost of white-washing its curved surface at the rate of ₹ 210 per 100 m^{2}.

**Solution:**

The slant height of the conical tomb is 25 m and the base diameter is 14 m.

The curved surface area of a right circular cone of base radius(r) and slant height(l) is πrl

Slant height, l = √r^{2} + h^{2}, where h is the height of the cone.

Diameter, d = 14 m

Radius, r = 14/2 m = 7 m

Slant height, l = 25 m

Curved surface area = πrl

= 22/7 × 7 m × 25 m

= 550m^{2}

Cost of the whitewashing at ₹ 210 per 100 m^{2}

= (210/100) × 550 = ₹ 1155

Thus, the cost of whitewashing the conical tomb is ₹1155.

**☛ Check: **NCERT Solutions for Class 9 Maths Chapter 13

**Video Solution:**

## The slant height and base diameter of a conical tomb are 25 m and 14 m respectively. Find the cost of white-washing its curved surface at the rate of ₹ 210 per 100 m².

Class 9 Maths NCERT Solutions Chapter 13 Exercise 13.3 Question 6

**Summary:**

It is given that the slant height and base diameter of a conical tomb is 25 m and 14 m respectively. The cost of white-washing its curved surface at the rate of ₹ 210 per 100 m² is ₹1155.

**☛ Related Questions:**

- Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m.
- Curved surface area of a cone is 308 cm² and its slant height is 14 cm. Find i) Radius of the base ii) Total surface area of the cone.
- A conical tent is 10 m high and the radius of its base is 24 m. Find i) Slant height of the tent. ii) Cost of the canvas required to make the tent, if the cost of 1 m² canvas is ₹ 70.
- What length of tarpaulin 3 m wide will be required to make conical tent of height 8 m and base radius 6 m? Assume that the extra length of material that will be required for stitching margins and wastage in cutting is approximately 20 cm (Use π = 3.14)

visual curriculum