Refer to the rectangle to answer the questions in Exercises 83 and 84.
83.Which one of the following is the best estimate of its area?
A. 50 B. 250 C. 2500 D. 100
84.Which one of the following is the best estimate of its perimeter?
A. 15 B. 250 C. 100 D. 30
Solve each problem. See Example 7.
85.Use the formula in Example 7to calculate the resonant frequency of a circuit to the near-
est thousand if henry and farad.
86.The threshold weight Tfor a person is the weight above which the risk of death increases
greatly. The threshold weight in pounds for men aged 40 – 49 is related to height hin
inches by the formula
What height corresponds to a threshold weight of 216 lb for a 43-year-old man? Round
your answer to the nearest inch and then to the nearest tenth of a foot.
87.According to an article in The World Scanner Re-
port,the distance D, in miles, to the horizon from
an observer’s point of view over water or “f lat”
earth is given by
where His the height of the point of view, in feet. If a person whose eyes are 6 ft above
ground level is standing at the top of a hill 44 ft above “flat” earth, approximately how far
to the horizon will she be able to see?
88.The time tin seconds for one complete swing of a simple pendulum, where Lis the length
of the pendulum in feet, and g, the acceleration due to gravity, is about 32 ft per , is
Find the time of a complete swing of a 2-ft pendulum to the nearest tenth of a second.
- Heron’s formulagives a method of finding the area of a triangle if the lengths of its sides
are known. Suppose that a, b, and care the lengths of the sides. Let sdenote one-half of
the perimeter of the triangle (called the semiperimeter); that is, Then
the area of the triangle is
Find the area of the Bermuda Triangle, to the nearest thousand square miles, if the “sides”
of this triangle measure approximately 850 mi, 925 mi, and 1300 mi.
a= 2 s 1 s-a 21 s-b 21 s-c 2.
s=^12 1 a+b+c 2.
t= 2 p
B
L
g
.
sec^2
D= 22 H,
h=12.3 23 T.
L=7.237 10 -^5 C=2.5 10 -^10
434 CHAPTER 8 Roots, Radicals, and Root Functions
√ 26
√ 98
Horizon
44 ft
6 ft
69.
A. 9 B. 10 C. 11 D. 12
70.
A. 7 B. 8 C. 9 D. 10
2 123.5 2 67.8
Find a decimal approximation for each radical. Round the answer to three decimal places.
See Example 6.
- 24100 80. 24250 81. 25 23.8 82. 25 98.4
- 282 - 291 23423 23555
29483 26825 2 284.361 2 846.104
Concept Check Choose the closest approximation of each square root.
