Question

the sum of the Length breadth and height of the cuboid is 20 centimetre and the length of its diagonal is 12 cm find the total surface area of the cuboid​

Answer 1

L+B+H=20 cm

$l ^{2} + b ^{2} + h ^{2} = 12cm$

$(l + b + h) ^{2} = l ^{2} + b^{2} + h ^{2} + 2(lb + bh + lh)$

(lb+bh+lh)
(20)square =12+2 (lb+bh+lh)
400=12+2 (lb+bh+lh)
400/12=2 (lb+bh+lh)

Answer 2

In cube,

length =height=breadth

there fore x+x+x = 20 cm

lets take a square in the cube

therefore 4x = 20

x=5

therefore length=breadth=height=5cm

total surface area of cube = 6a^2

6x5x5

total surface area of cube = 150 cm2