Question

The aspect ratio​ (length to​ width) of an lcd computer monitor is 5​ : 4. the lcd monitor of a toshiba laptop computer has a perimeter of 32.4 inches. what is the diagonal measure of the​ screen? round to the nearest tenth of an inch.

Answer 1

Formula of perimeter =
`2(W+H)`

So, 2W + 2H = 32.4 ... (1)

Ratio = 5:4

So,
`(W)/(H) =(5)/(4)`

4W - 5H = 0 ... (2)

Solve equation (1) and (2).

W = 9.0 and H = 7.2

Use the Pythagorean theorem,

`W^(2) + H^(2) = D^(2)`

`D^(2) = (9.0)^(2)  + (7.2)^(2)`

`D^(2) = 132.84`

D = 11.52

D = 11.5

Hence, the measure of diagonal is 11.5 inches.