The length, breadth and height of a rectangular solid are in the ratio 5:4:2. If the total surface area is 1216 cm2, find the length, breath and height of the solid.
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Let length breadth and height be 5x, 4x and 2x respectively.
Now, T.S.A of solid=2 (lb + bh +lh)
2 (5x × 4x+4x×2x +5x ×2x )=1216
2 (20x^2+8x^2+10x ^2)=1216
2×38x^2=1216
38x^2=1216/2
x^2=608/38
x^2=16
x=4
so,length =5×=5×4=20cm
breadth=4×=4×4=16cm
height=2×=2×4=8cm
Now, T.S.A of solid=2 (lb + bh +lh)
2 (5x × 4x+4x×2x +5x ×2x )=1216
2 (20x^2+8x^2+10x ^2)=1216
2×38x^2=1216
38x^2=1216/2
x^2=608/38
x^2=16
x=4
so,length =5×=5×4=20cm
breadth=4×=4×4=16cm
height=2×=2×4=8cm
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