Solution:

Given side of the cube, a = 28 cm

Radius of the cylinder, r = 28/2 = 14 cm

Height of the cylinder, h = 28 cm

Volume of the cube = a³

= 28³

= 28×28×28

= 21952 cm³

Volume of the cylinder = r²h

= (22/7)×14²×28

= 22×2×14×28

= 17248 cm³

Total volume of the solid = Volume of the cube + volume of the cylinder

= 21952+17248

= 39200 cm³

Cost of 1 cm³ glass = Rs. 0.75

Total cost of glass = 39200×0.75

= Rs. 29400

Hence the cost of making the trophy is Rs. 29400.