Power consumed by a resistance

Two resistors $R_1=1.2\ \Omega$R, start subscript, 1, end subscript, equals, 1, point, 2, space, \Omega and $R_2=1.8\ \Omega$R, start subscript, 2, end subscript, equals, 1, point, 8, space, \Omega are connected as shown below.

The potential difference between the terminals is $V_{\text{AB}}=3.6\ \text V$V, start subscript, start text, A, B, end text, end subscript, equals, 3, point, 6, space, start text, V, end text.