Step-by-step explanation:
Solution,
In the given cuboid, area of total surface (A)=280 cm²
Breadth ( b ) = 5 cm
Height ( h ) = 6 cm
Total surface area of cuboid = 2 ( lb + bh + lh )
or , Area = 2 ( lb + bh + lh )
or , 280 = 2 ( l × 5 + 5 × 6 + l × 6 )
or , 280 = 2 ( 11 l + 30 )
or , 2 ( 11 l + 30 ) = 280
or , 11 l + 30 = 280 ÷ 2
or , 11 l + 30 = 140
or , 11 l = 140 - 30
or , 11 l = 110
or , l = 110 ÷ 11
l = 10
Thus, the length is 10 cm...
