Question

plzz ans. Q.20....its urgnt plz

Answer 1

Given,

Radius of cylindrical part = Radius of hemispherical part = 3.5 cm

Total height of souvenir = 10cm 

Surface area of article = CSA of cylindrical part + 2 × CSA of hemispherical 

= 2πrh + 2 × 2πr²

= 2π × 3.5 × 10 + 2 × 2π × 3.5 × 3.5

= 70π + 49π

= 119π

= 17 × 22

= 374 cm²

Now the price of polishing will be = Surface area of article × cost of polishing

= 374 × 10 

= 3740 

So the cost will be 3740 Rupees

Answer 2

Radius of hemisphere = Radius of cylinder = 3.5 cm

Height of the cylinder = 10 cm

T.S.A of the wooden souvenir = C.S.A of cylinder + 2 × C.S.A of hemisphere

C.S.A of cylinder = 2πrh
= 2×22 / 7× 3.5 × 10
= 220 cm²

C.S.A of hemisphere = 2 π r²
.. = 2×22 / 7× 3.5 × 3.5
= 77 cm ²
C.S.A of 2 hemispheres = 77 × 2 = 154 cm²


T.S.A of the wooden souvenir = 220 cm² + 154 cm²
= 374 cm²

Cost of polishing the souvenir for 1 cm² = Rs 10
Total cost of polishing the souvenir for 374 cm² = 374 × 10
= Rs 3740


Please mark brainliest ....