Bonjouro! Firstly, as this is my first post here, I would like to say thank you to everyone who is a part of the site and Hello! I've used this forum a number of times, but this is the first time I've posted here as this user! If the flexural stiffness of a beam is 25 MNm^2, and the beam is made of steel, what is the breadth and depth of the beam (or at least beam dimensions that would work) I did this by saying I = bd^3/12 EI = 25,000,000,000 Nmm^2 E = 200,000 MPa I = 1,500,000mm^4 Using I = b*d^3 / 12 Assuming breadth (b) is 50mm, I get depth (d) as 31.072mm, but apparently this is wrong and I cannot figure out why :'( My question comes from this thing I found on the internet, which gives me these FEA results, but they don't match up! View post on imgur.com Please help PhysicsForum guys! You're my only hope!