1.

The decorative block shown in the figure is made of two solids, a cube and a hemisphere. The base of the block is a cube with edge 5 cm, and the hemisphere fixed on the top has a diameter of 4.2 cm. The total surface area of the block is ..... (A) 150 cm2(B) 160.86 cm2(C) 162.86 cm2(D) 163.86 cm2

Answer»

The correct option is: (D) 163.86 cm2

Explanation:

Total surface area of the block = Total surface area of cube + Curved surface area of hemisphere - Area of base of hemisphere

= 6 x (5)2 + 2π x (2.1)2 - π x (2.1)2 

= 150 + π x (2.1)2 = 150 + 13.86 = 163.86 cm2



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