Three equal cubes are placed adjacently in a row . Find the ratio of the total surface area of the resulting cubeoid to that of the sum of the total surface areas of the three cubes
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Tsa of cuboid = sum of the tsa of 3 tubes
2(lb+bh+hl)= 6a²+6a²+6a²
lbh = 18a²
when we place three cubes adjacently then dimensions of cuboid are
l=a+a+a=3a, b=a, h=a
by substituting these values in 2(lb+bh+hl) we get
2(3a×a+a×a+a×3a) = 18a²
(3a²+a²+3a²) = 18a²/2
7a² = 9a²
7:9
therefore ratio of tsa's of cuboid and cube = 7:9
2(lb+bh+hl)= 6a²+6a²+6a²
lbh = 18a²
when we place three cubes adjacently then dimensions of cuboid are
l=a+a+a=3a, b=a, h=a
by substituting these values in 2(lb+bh+hl) we get
2(3a×a+a×a+a×3a) = 18a²
(3a²+a²+3a²) = 18a²/2
7a² = 9a²
7:9
therefore ratio of tsa's of cuboid and cube = 7:9
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