For a given cross-section, consisting of channel and equal angles, or from an I-beam and the equal angles, or of channel and I-beam is required: 1) define the position of the center of gravity; 2) find the axial and centrifugal moments of inertia with respect to random axes passing through the center of gravity; 3) determine the direction of the principal central axes; 4) to find the moments of inertia about the main central axis; 5) draw a cross-section of a scale of 1: 2.