Here, we will have to know the outer and inner edge dimensions.

The volume of the unequal L section = cross-sectional area x Length

Where X_{1 }is outer edge width, Y_{1} is outer edge height and x_{2} is inner edge width, y_{2 }is inner edge height.

Let us consider a 1 m long unequal L section of outer edge width 60 mm = 0.060 m, outer edge height = 30 mm = 0.030 m and inner edge width 55 mm = 0.055 m , inner edge height = 25 mm = 0.025 m.

So, Volume of the L section = [ ( 0.060 × 0.030 ) – ( 0.055 × 0.025 ) ] × 1 = 0.000425 m^{3}

Hence, mass of the L section = density × volume = 7900 × 0.000425 = 3.3575 kg

In this way, we can calculate the weight of an unequal-length L – section beam

Here, we will have to know the outer and inner edge dimensions.

Volume of the L section = cross-sectional area × Length

V= A x L = (( X_{1} × Y_{1} ) – (x_{2} × y_{2} )) × L

Where X_{1 }is outer edge width, Y_{1} is outer edge height and x_{2} is inner edge width, y_{2 }is inner edge height.

Let us consider a 1 m long L section of outer edge width 30mm = 0.030m, outer edge height = 30 mm = 0.030 m and inner edge width 25 mm = 0.025 m , inner edge height = 25 mm = 0.025 m.

So, Volume of the L section = [ (0.030 × 0.030) – (0.025 × 0.025) ] × 1 = 0.000275 m^{3}

Hence, mass of the L section = density × volume = 7900 × 0.000275 = 2.1725 kg

By using this formula we can calculate the mass of equal length L – section beam of different dimensions.