In the figure ABC ~ PQR. What is the value of x?

Since triangle ABC ~ triangle PQR
AB/PQ = BC/QR = AC/PR
=> 4/x = 6/7.2 = 5/6

Taking
4/x = 5/6
4*6 = 5*x
24 = 5x
X=24/5
x=4.8 cm