1. How many points are enough to fix a line?

2. Two intersecting lines intersect in

3. How many lines can pass through one given point?

4. How many lines can pass through two given points?

5. How many vertices are there in a triangle?

6. How many sides are there in a triangle?

7. How many angles are there in a triangle?

8. How many vertices are there in a quadrilat¬eral?

9. How many sides are there in a quadrilateral?

10. How many angles are there in a quadrilateral?