Basic Mathematics for College Students

Find the area of each circle given the following information. Give
the exact answer and an approximation to the nearest tenth.
See Example 3.

33. 
    
    
    
    34. 
        
    
    
    
    


34. Find the area of a circle with diameter 18 inches.


35. Find the area of a circle with diameter 20 meters.

Find the total area of each figure. Assume each arc is a semicircle.
Round to the nearest tenth.See Example 4.

TRY IT YOURSELF

Find the area of each shaded region. Round to the nearest tenth.

8 ft 8 ft

h = 9 in.

13 in.

r = 4 in.

8 in.

4 in. 8 in.

10 in

4 in.

4 cm

8 cm

10 in.

6 in.

12 cm

12 cm

14 ft

6 in.

45. Find the circumference of the circle shown below.
    Give the exact answer and an approximation to the
    nearest hundredth.


46. Find the circumference of the semicircle shown
    below. Give the exact answer and an approximation
    to the nearest hundredth.


47. Find the circumference of the circle shown below if
    the square has sides of length 6 inches. Give the exact
    answer and an approximation to the nearest tenth.


48. Find the circumference of the semicircle shown below
    if the length of the rectangle in which it is enclosed is
    8 feet. Give the exact answer and an approximation
    to the nearest tenth.


49. Find the area of the circle shown below if the square
    has sides of length 9 millimeters. Give the exact
    answer and an approximation to the nearest tenth.


50. Find the area of the shaded semicircular region shown
    below. Give the exact answer and an approximation to
    the nearest tenth.

6.5 mi

8 ft

25 cm

50 yd

9.8 Circles 799