Curved Surface Area of Cone | Exercise 13.3 Q4

Question 4: 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 Rs.70.

Explanatory Answer | Exercise 13.3 Q4

Given Data
Radius of the conical tent, r = 24 m
Height of the conical tent, h = 10 m

Part (i): Find Slant Height of Cone

Square of the slant height of the cone, l² = h² + r²
l² = 10² + 24²
l² = 100 + 576 = 676
l² = 676
l = 26 m

Part (ii): Find CSA of cone and Cost of making Conical Tent

Curved surface area of cone = π × r × l
Take π = \\frac{22}{7})
= \\frac{22}{7}) × 24 × 26
= \\frac{13728}{7}) m²
Cost of the canvas required at the rate of Rs.70 per m² = \\frac{13728}{7}) × 70
= Rs.1,37,280

Exercise 13.1 | Surface Area of Cubes & Cuboids

1. Class 9 Exercise 13.1 Question 3 | Height of hall ▶
2. Class 9 Exercise 13.1 Question 6 | TSA of Herbarium ▶
3. Class 9 Exercise 13.1 Question 7 | Shanti Sweets ▶

Exercise 13.2 | Surface Area of Cylinders

1. Class 9 Exercise 13.2 Question 3 | CSA TSA of Metal Pipe ▶
2. Class 9 Exercise 13.2 Question 4 | Roller & Playground ▶
3. Class 9 Exercise 13.2 Question 9 | Cylindrical Petrol Tank ▶
4. Class 9 Exercise 13.2 Question 10 | CSA of Decorative Lampshade ▶

Exercise 13.3 | Surface Area of Cones

1. Class 9 Exercise 13.3 Question 5 | Length of Tarpaulin 3 m wide ▶
2. Class 9 Exercise 13.3 Question 8 | Cost of painting conical barricades ▶

Exercise 13.4 | Surface Area of Spheres & Hemispheres

1. Class 9 Exercise 13.4 Question 8 | Outer CSA of hemispherical bowl ▶
2. Class 9 Exercise 13.4 Question 9 | Surface area of sphere & Cylinder ▶