a level physics-momentsWatch
sorry what I meant is don't you need the weight to work out the moments of the support idk
N.B. the total moments cw = 0 and you will need to take moments about one of the supports to eliminate one variable from the equation and make it solvable
once you’ve found R2 you know the system is in equilibrium to therefore the sum of the forces acting down (weight of ruler) is equal to the sum of forces acting up (R1 and R2). this means R1 R2 = 1.2 therefore R1 =1.2 - R2.
sorry this was a mess of an explanation but i’ll attach a picture of my working to hopefully make it easier to understandAttachment 873804