Q3 of 64 Page 80

Two cubes each of volume 64 cm3 are joined to form a cuboid. Find the L.S.A and T.S.A of the resulting solid.

Given:

volume of given cube = 64cm3


Side = a cm


Volume = (a)3


64 = (a)3


a = 4cm


two cubes are joined together.


Length of resultant cube = 4+4 = 8cm


Breadth = 4cm


Height = 4cm


(a) LSA of cuboid = 2(lh+hb)


= 2(8(4) + 4(4))


= 2(32+16)


= 2(48) = 96cm2


⇒ LSA of cuboid = 66m2


(b)TSA of cuboid = 2(lh+hb+lb)


= 2(8(4) + 4(4) + 8(4))


= 2(32+16+32)


⇒ TSA of cuboid = 2(80) = 160m2


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