Answer:
63.59 in²
Step-by-step explanation:
The formula to find the area of a square: a², where a is the side.
The formula to find the area of a circle: πr², where r is the radius (diameter ÷ 2), and the pi is alterable (3.14 or 3.142 or 22/7).
1) Find the diameter of the circle. The side of a square is the diameter.
a²
a = √81
a = 9
2) Plug the values into the formula of the area of a circle. 9 ÷ 2 = 4.5 (radius).
= 3.14 x 4.5²
= 3.14 x 20.25
= 63.585
3) Round off the result to the nearest hundredth.
= 63.59
Remember that transformation between Cartesian and polar system are:
x=r*cos(α)
y=r*sin(α)
From this we can conclude that:
r=√(x^2 + y^2)
Using trigonometry transformations we can write:
r=sin(2α) = 2sin(α)cos(α)
Now we can multiply both sides with r^2:
r^3 = 2(r*sin(α))*(r*cos(α))
Now using some replacements we can write:
(x^2 + y^2)^(3/2) = 2*x*y
Since the data follows a normal distribution, the 68-95-97 rule can be used to describe the number of people falling under N standard deviations from the mean. Since the standard deviation is 1, hemoglobin levels of 13 -15 g/dL contains 68% of the sample, or 136 people. This means the 32 people have less than 13 g/dL and 32 people have more than 15 g/dL.
It shows that there is only one way to get to 10 which is by multiplying it by 1