Two o'clock.
2. It is known that the line segment AB= 10cm, the distance to point A is equal to 7 cm, and the distance to point B is equal to 6 cm.
Two o'clock.
3. The locus of the vertex D of △DBC with the same area as △ABC is
A pair of parallel lines.
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The first question, draw an arc with A and B as the center and 6 as the radius, and the intersection point is C, and C' is what you want;
The second question is, draw an arc with A and B as the center and 7 and 6 as the radius respectively, and the intersection point is C, and C' is what you want;
3. The vertices of a triangle with a fixed base and equal triangle area are two straight lines and two parallel lines with the same distance from the base.