What is (-2/3) x (-3/4)
2 answers:
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Answer:
Remember that the area of a square of sidelength L is:
A = L^2
And the area of a circle of diameter D is:
A = pi*(D/2)^2
If we inscribe a square in a circle, we will get four segments, like the ones shaded in the image below:
Notice that the diameter of the circle will be equal to the diagonal of the square.
And the diagonal of a square of side length L is:
d = √(2)*L
knowing that the side length of our square is 6 inches, the diameter of the circle will be:
D = √2*6in
Now, the total area of the four shaded parts will be equal to the difference between the area of the circle and the area of the square.
The area of the circle is:
A = pi*(√2*6in/2)^2 = (pi/2)*36in^2
The area of the square is:
A' = (6in)^2 = 36in^2
The difference is:
A - A' = (pi/2)*36in^2 - 36in^2 = (pi/2 - 1)*36in^2
And there are 4 of these segments, then the area of every single one is one-fourth of that:
a = (1/4)*(pi/2 - 1)*36in^2 = (pi/2 - 1)*9 in^2
The area of each segment is:
a = (pi/2 - 1)*9 in^2
if we replace pi by 3.14, the exact area will be:
a = (3.14/2 - 1)*9in^2 = 5.13 in^2
Answer:
1) Between 12.5 miles and 21.7 miles.
2) b) 75%
3) c) 95%
4) Between 13.7 miles and 20.5 miles.
Step-by-step explanation:
Empirical Rule:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviations of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
Chebyshev Theorem:
The Chebyshev Theorem can also be applied to non-normal distribution. It states that:
At least 75% of the measures are within 2 standard deviations of the mean.
At least 89% of the measures are within 3 standard deviations of the mean.
An in general terms, the percentage of measures within k standard deviations of the mean is given by .
1) According to Chebyshev's theorem, at least 36% of the commute distances lie between miles and miles.
Within k standard deviations of the mean, and k is found when . So
Within 1.25 standard deviations of the mean.
1.25*3.7 = 4.6 miles
17.1 - 4.6 = 12.5 miles
17.1 + 4.6 = 21.7 miles
Between 12.5 miles and 21.7 miles.
2) According to Chebyshev's theorem, at least of the commute distances lie between 9.7 miles and 24.5 miles.
17.1 - 9.7 = 24.5 - 17.1 = 7.4 miles, so within 2 standard deviations of the mean, which is 75%, option B.
3) Suppose that the distribution is bell-shaped. According to the empirical rule, approximately of the commute distances lie between 9.7 miles and 24.5 miles.
Within 2 standard deviations of the mean, by the Empirical Rule, which is 95%, option c.
4) Suppose that the distribution is bell-shaped. According to the empirical rule, approximately 68% of the commute distances lie between miles and miles.
Within 1 standard deviation of the mean.
17.1 - 3.4 = 13.7
17.1 + 3.4 = 20.5
Between 13.7 miles and 20.5 miles.