1. How do we know that a line must be straight and that a plane must be flat?
2. Is the interior of an angle part of the angle? Explain.
3. What kind of angle is formed when the minute

hand of a clock is on 12 and the hour hand is on:

a. 2? b. 3? c. 5? d. 6? e. 10?

4. Convert to degrees, minutes, and seconds.

a. 43.07 b. 94.631

5. When two lines intersect, they divide the plane into four regions. What is the largest number of regions a plane is divided into by:

a. Three lines? b. Four lines?

c. Five lines? d. n lines?

6. a. What angle has the same measure as its

complement?

b. What angle has the same measure as its

supplement?

c. What is the measure of the angle whose supplement is five times its complement?

7. How many degrees does the earth rotate in 1 hr? One minute?

8. If two angles form a congruent linear pair, what is true about the sides of the angles?

9. Write two or three paragraphs that briefly explain how the concepts of this section are built from the basic notions of a point, line, and plane.

10. With several of your pers, discuss whether any of the terms in this section have nongeometrical meanings. If so, what are they? Do the geometrical and the nongeometrical meanings have any connection to one another? If so, how?