How to calculate the moment of inertia of a system with multiple bodies?

[CollinsArg]

Homework Statement

Calculate the moment of inertia in the OO' axis of the following figure (image attached).

Homework Equations

The relevant equations are in the image,
except: I = I_cm + m.h² (formula of moment of inertia to change the axis from the centre of mass to a parallel axis).

The Attempt at a Solution

I tried to find the moment of inertia of each figure separately/individually depending of the OO' axis by the formula give in "relevant equations" then sum all up to find the total moment of inertial of the system. Is this right? I'm not sure how to evidence this is correct

 

[kuruman]

You need to show more work before one can tell whether your answer is correct. Your method is correct. You have 5 bodies, you need to calculate the moment of inertia about axis OO' for each one separately then add all the results. If you want someone to check your work, please provide the 5 separate moments of inertia, not just the final answer.