A conical fire work is of base diameter 10 centimetres and height 12 centimetres. 10000 such fireworks are to be wrapped in colour paper. The price of the colour paper is 2 rupees per square metre. What is the total cost?

height of the cone (h) = 12 cm

Diameter of a cone = 10cm

Base radius

l = slant height

Applying Pythagoras theorem, we get:

l = √(h² + r_b²)

= √(12² + 5²)

= √(144 + 25) = √169 cm = 13cm

We know that, Curved surface area of cone = πr_bl

Where r_b = base radius and l = slant height

Curved surface area of cone = π× 5× 13 = 65π cm²

Surface area of base = πr_b² = π × 5² = 25π cm².

Total surface area = (65 + 25)π = 90π cm² = 90× 3.14 = 282.6cm²

Surface area of 10000 fire works = 282.6 × 10000 = 2826000 cm².

So cost of colour paper = 282.6 × 2 = Rs 565.20