Question

A bus stop is barricated from the remaining part of the road by using
50 hollow cones made of
recycled cardboard. Each one has a base
diameter of 40 cm and height 1 m. If the outer side of each of the cones is to be painted and the Cost of painting rs25m2 ,what will be cost of painting all these cones? (use pyee=3.14) and underroot(1.04 =1.02.)​

Answer 1

Answer:

Curved surface area of cone will be painted=πrl

h=1m;radius=

2

40

​

=20cm=0.2m

and let l be the slant height,

∴l

2

=h

2

+r

2

=1

2

+0.2

2

⇒l=

1+0.04

​

=

1

​

.04=1.02m  (∵

1

​

.04=1.02 is given in the question)

⇒Curved surface area of 1 cone=πrl=(3.14×0.2×1.02)m

2

=0.64046m

2

⇒ Curved surface area of 50 cones=50×0.64046=32.028m

2

Cost of painting 1m

2

=Rs.12

∴ Cost of painting 32.028m

2

=(12×32.028)=384.336m

2

≈384.34

∴ Cost of painting 50 cones is Rs.384.84

Step-by-step explanation: