i need help ASAP

Perimeter =  2 (W + L)

And we  know that

112 =   2 ( W  +  L )    divide  both sides  by  2

56  = W  +  L

56  -   W   =   L

And

L             4

__  =     ___    so

W            3

56 - W            4  

______   =  _____       cross-multiply

     W               3 

3 ( 56 - W )   =  4W

168  - 3W  = 4W        add W to  both sides

168  =   7 W               divide  both sides  by 6

24  = W

And  L =   56 -  24  =   32

The perimeter of Dawna's new flat screen television is 112 inches. The ratio of its length to width is 4:3. Write and solve an algebraic equation to determine the dimensions of the television. 

[( 112/14 ) *8 ] / 2  :  [( 112/14 ) *6 ] / 2  =  32  :  24  =  4 : 3