can you please help me with the steps of the solution of this question

Problem 6 The diagram shows a frictionless piston of mass 0.2kg, diameter 3cm, and negligible thickness in a tube that separates two liquids. Liquid 1 has density 3400kg/m3. Both liquids are open to atmospheric pressure air on top and the system is in equilibrium. The lengths shown in the diagram are a=3cm and b=7cm. Neglecting surface tension, calculate the density of liquid 2