Describe the geometric figure in the section labeled '4'. What properties are indicated by the markings?

Figure 4:

• The figure is a quadrilateral with vertices A, B, C, and D.
• A diagonal BD is drawn.
• The sides AD and BC are marked with single dashes, indicating AD = BC.
• The angles at D and C are marked with arcs, indicating angle ADC = angle BCD.
• A quadrilateral with one pair of opposite sides equal and the angles at the ends of the other side equal is an isosceles trapezoid. However, here we have equal non-parallel sides and equal base angles if we consider AB and DC as bases.
• If AD and BC are non-parallel sides and they are equal, and the base angles (angles at D and C) are equal, then it is an isosceles trapezoid.
• Let's re-examine: AD = BC (sides) and angle D = angle C (angles). This implies that AB is parallel to DC. If AD and BC are the non-parallel sides, and they are equal, and the angles at the base DC are equal, it is an isosceles trapezoid.

Answer: Figure 4 represents an isosceles trapezoid, where the non-parallel sides AD and BC are equal in length, and the base angles at vertex D and vertex C are equal.