The length and width of the screen of the tv set are in the ratio 16: 9. if the perimeter of the screen is 180cm find its length and width

Let
x> the length of the screen of the TV
y> the width of the screen of the TV

we know that
perimeter of the screen=2*[x+y]
perimeter=180 cm
180=2*[x+y]> 90=x+y> equation 1

x/y=16/9>x=(16/9)*y> equation 2

substitute the equation 2 in equation 1
90=[(16/9)*y]+y> (25/9)*y=90> y=32.4 cm
x=(16/9)*32.4> x=57.6

the answer is
the length of the screen of the TV is 57.6 cm
the width of the screen of the TV is 32.4 cm