Question

the length, breadth and height of a cuboid are in the ratio 5:4:2 and its total sur face area is 1216 cm2. Find the dimensions of the cuboid.

Answer 1

l = 5 x
b= 4 x
h= 2x

therefore

T*S*A = 2(lb+lh+bh)
=2(5x×4x+5x×2x+4x×2x)
=2(20+10+8)x^2
1216 =76x^2
x^2 = 1216/76
x^2 =16
x=4

therefore
l = 20
b = 16
h = 8



i hope it will help you

Answer 2

$<b><h3><font color ="red">let the length be 5x let the breadth be 4x let the height be 2x total surface area =1216 cm^{2} 2*(lb +bh hl) = 1216 CM ^{2} 2 *(5x^{2}*4x^{2}+4x^{2}*2x^{2} +2x^{2} *5x^{2} ) =1216 2 *(20x +8x +10x) =1216 2 *38x =1216 x^2= 1216/76 =16 x = 16^2 =4 •length =5x =5* 4= 20CM • breadth =4x =4*4 =16CM •height = 2x =2 *4 =8cm$