A rectangular LCD has an area of 480 cm² and a perimeter of 92 cm. If the size of the LCD is defined in term of length of the diagonal, then what is the size of the LCD?

34 cm

We have,

The perimeter of a rectangular LCD = 92m.

Area = 480m²

Then 2(l + b) = 92

L+ b = 46 … (A)

And lb = 480 ….(B)

Now, we know that,

 (l - b)² = (l + b)²  - 4lb

= (l –b)² = 2116 - 4 × 480

= (l –b)² = 2116 - 1920 = 196

(l - b) = 14 ….(C)

From, equation (A) and (C)

 B = 16, and l = 30

Then (Diagonal)² = 30²  + 16²

(Diagonal)²  = 1156

Diagonal = 34.