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The sum of the length,breadth and height of a cuboid is 38cm and the length of its diagonal is 22cm. Find the surface area of cuboid.



You have two equations,
Square both of them and subtract one from the other, you get,
Hence, Surface Area, S = 960 cm².
1 1 1
Thanks Jackie. But the answer provided in my book is 960 cm²
Oh am sorry. That was my mistake. Thanks a lot. :)
Happy to help :-)
But how did we get 2(lb+bh+hl)= 38²-22² ??
The Brainliest Answer!
Let length =l , breadth = b and height =h
ATQ  l+b+h= 38 cm                        (1)
     and  √(l² +b² + h²) = 22 cm         (2)
Surface area of cuboid = 2(lh+ lb+ bh)
                                  = (l+b+h)² - (l²+b²+h²)
                                  = 38² -22²
                                  = 960
Surface area of cuboid is 960 cm²

3 4 3
Can u explain???
cuboid has six faces. Opposite faces are equal. surface area of each face are- lb, bh and lh . so the total surface area = 2lb+2 bh+2 lh
So why did we put it as (l+b-h)² - (l²+b²+h²) ??
we know (l+b-h)²= l²+b²+h² + 2(lb+bh+lh) that gives 2(lb+bh+lh)=(l+b-h)² - (l²+b²+h²)
Okay. :)
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