The volume of the rectangular pipe = cross-sectional area x Length
V = A × L = ( ( X1 × Y1 ) – ( x2 × y2 ) ) × L
Where X1 is outer edge width, Y1 is outer edge height and x2 is inner edge width, y2 is inner edge height.
Let us consider a 1m long rectangular pipe of outer edge width 30mm = 0.030m, outer edge height = 25 mm = 0.025 m and inner edge width 20 mm = 0.020 m , inner edge height = 15 mm = 0.015 m.
So, Volume of the rectangular pipe = [ (0.030 × 0.020 ) – ( 0.025 × 0.015 ) ] × 1 = 0.000225 m3
Hence, mass of the rectangular pipe = density × volume = 7900 × 0.000225 = 1.7775 kg
By using this formula we can calculate the mass of rectangular pipes of different dimensions.