Basic Mathematics for College Students

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798 Chapter 9 An Introduction to Geometry

VOCABULARY

Fill in the blanks.

1. A segment drawn from the center of a circle to a
   point on the circle is called a.


2. A segment joining two points on a circle is called a
   .


3. A is a chord that passes through the center
   of a circle.


4. An arc that is one-half of a complete circle is a
   .


5. The distance around a circle is called its
   .


6. The surface enclosed by a circle is called its.


7. A diameter of a circle is as long as a radius.


8. Suppose the exact circumference of a circle is 3pfeet.
   When we write feet, we are giving an
   of the circumference.

CONCEPTS

Refer to the figure below, where point 0 is the center of the circle.

9. Name each radius.


10. Name a diameter.


11. Name each chord.


12. Name each minor arc.


13. Name each semicircle.


14. Name major arc ABDin
    another way.


15. a. If you know the radius of a circle, how can you
    find its diameter?
    b. If you know the diameter of a circle, how can you
    find its radius?


16. a. What are the two formulas that can be used to find
    the circumference of a circle?
    b. What is the formula for the area of a circle?


17. If is the circumference of a circle and is its
    diameter, then.


18. If is the diameter of a circle and is its radius, then
    .


19. When evaluating , what operation should be
    performed first?


20. Round to the nearest
    hundredth.

p3.141592653589...

p(6)^2

D r

D r

CD

C D

C9.42

NOTATION

Fill in the blanks.

21. The symbol ABis read as “ .”


22. To the nearest hundredth, the value of pis.


23. a. In the expression , what operations are
    indicated?
    b. In the expression , what operations are
    indicated?


24. Write each expression in better form. Leave pin your
    answer.

a. b. c.

GUIDED PRACTICE

The answers to the problems in this Study Set may vary slightly,

depending on which approximation of pis used.

Find the circumference of the circle shown below. Give the exact

answer and an approximation to the nearest tenth.

See Example 1.

Find the perimeter of each figure. Assume each arc is a semicircle.

Round to the nearest hundredth.See Example 2.

29. 
    
    
    
    30. 
        
    
    
    
    


30. 
    
    
    
    32. 18 in.
    
    
    
    

18 in.

10 in.

6 m

8 m 8 m

8 ft

3 ft

12 cm

10 cm

6 m 10 mm

8 in.

4 ft

p

25

3

p(8) 2 p(7)

pr^2

2 pr

SECTION 9.8 STUDY SET