Answer:
121
Step-by-step explanation:
Answer:
c=8+3.75x, where:
c is the cost to go to the ice skating ring
x is the number of hours
Step-by-step explanation:
From the information given, the cost to go to the ice skating ring is equal to the cost to rent ice skates plus the result of multiplying the cost to skate per hour for the number of hours and the equation would be:
c=8+3.75x, where:
c is the cost to go to the ice skating ring
x is the number of hours
1. Divide wire b in parts x and b-x.
2. Bend the b-x piece to form a triangle with side (b-x)/3
There are many ways to find the area of the equilateral triangle. One is by the formula A=
![\frac{1}{2}sin60^{o}side*side= \frac{1}{2} \frac{ \sqrt{3} }{2} (\frac{b-x}{3}) ^{2}= \frac{ \sqrt{3} }{36}(b-x)^{2}](https://tex.z-dn.net/?f=%20%5Cfrac%7B1%7D%7B2%7Dsin60%5E%7Bo%7Dside%2Aside%3D%20%20%20%5Cfrac%7B1%7D%7B2%7D%20%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B2%7D%20%20%28%5Cfrac%7Bb-x%7D%7B3%7D%29%20%5E%7B2%7D%3D%20%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B36%7D%28b-x%29%5E%7B2%7D%20%20%20%20)
A=
![\frac{ \sqrt{3} }{36}(b-x)^{2}=\frac{ \sqrt{3} }{36}( b^{2}-2bx+ x^{2} )=\frac{ \sqrt{3} }{36}b^{2}-\frac{ \sqrt{3} }{18}bx+ \frac{ \sqrt{3} }{36}x^{2}](https://tex.z-dn.net/?f=%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B36%7D%28b-x%29%5E%7B2%7D%3D%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B36%7D%28%20b%5E%7B2%7D-2bx%2B%20x%5E%7B2%7D%20%20%29%3D%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B36%7Db%5E%7B2%7D-%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B18%7Dbx%2B%20%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B36%7Dx%5E%7B2%7D)
Another way is apply the formula A=1/2*base*altitude,
where the altitude can be found by applying the pythagorean theorem on the triangle with hypothenuse (b-x)/3 and side (b-x)/6
3. Let x be the circumference of the circle.
![2 \pi r=x](https://tex.z-dn.net/?f=2%20%5Cpi%20r%3Dx)
so
![r= \frac{x}{2 \pi }](https://tex.z-dn.net/?f=r%3D%20%5Cfrac%7Bx%7D%7B2%20%5Cpi%20%7D%20)
Area of circle =
![\pi r^{2}= \pi ( \frac{x}{2 \pi } )^{2} = \frac{ \pi }{ 4 \pi ^{2} }* x^{2} = \frac{1}{4 \pi } x^{2}](https://tex.z-dn.net/?f=%20%5Cpi%20%20r%5E%7B2%7D%3D%20%5Cpi%20%20%28%20%5Cfrac%7Bx%7D%7B2%20%5Cpi%20%7D%20%29%5E%7B2%7D%20%3D%20%5Cfrac%7B%20%5Cpi%20%7D%7B%204%20%5Cpi%20%5E%7B2%7D%20%20%7D%2A%20x%5E%7B2%7D%20%3D%20%5Cfrac%7B1%7D%7B4%20%5Cpi%20%7D%20x%5E%7B2%7D%20%20)
4. Let f(x)=
![\frac{ \sqrt{3} }{36}b^{2}-\frac{ \sqrt{3} }{18}bx+ \frac{ \sqrt{3} }{36}x^{2}+\frac{1}{4 \pi } x^{2}](https://tex.z-dn.net/?f=%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B36%7Db%5E%7B2%7D-%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B18%7Dbx%2B%20%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B36%7Dx%5E%7B2%7D%2B%5Cfrac%7B1%7D%7B4%20%5Cpi%20%7D%20x%5E%7B2%7D)
be the function of the sum of the areas of the triangle and circle.
5. f(x) is a minimum means f'(x)=0
f'(x)=
![\frac{ -\sqrt{3} }{18}b+ \frac{ \sqrt{3} }{18}x+\frac{1}{2 \pi } x](https://tex.z-dn.net/?f=%5Cfrac%7B%20-%5Csqrt%7B3%7D%20%7D%7B18%7Db%2B%20%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B18%7Dx%2B%5Cfrac%7B1%7D%7B2%20%5Cpi%20%7D%20x)
=0
![\frac{ -\sqrt{3} }{18}b+ \frac{ \sqrt{3} }{18}x+\frac{1}{2 \pi } x=0](https://tex.z-dn.net/?f=%5Cfrac%7B%20-%5Csqrt%7B3%7D%20%7D%7B18%7Db%2B%20%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B18%7Dx%2B%5Cfrac%7B1%7D%7B2%20%5Cpi%20%7D%20x%3D0)
![(\frac{ \sqrt{3} }{18}+\frac{1}{2 \pi }) x=\frac{ \sqrt{3} }{18}b](https://tex.z-dn.net/?f=%28%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B18%7D%2B%5Cfrac%7B1%7D%7B2%20%5Cpi%20%7D%29%20x%3D%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B18%7Db)
![x= \frac{\frac{ \sqrt{3} }{18}b}{(\frac{ \sqrt{3} }{18}+\frac{1}{2 \pi }) }](https://tex.z-dn.net/?f=x%3D%20%5Cfrac%7B%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B18%7Db%7D%7B%28%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B18%7D%2B%5Cfrac%7B1%7D%7B2%20%5Cpi%20%7D%29%20%7D%20)
6. So one part is
![\frac{\frac{ \sqrt{3} }{18}b}{(\frac{ \sqrt{3} }{18}+\frac{1}{2 \pi }) }](https://tex.z-dn.net/?f=%20%5Cfrac%7B%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B18%7Db%7D%7B%28%5Cfrac%7B%20%5Csqrt%7B3%7D%20%7D%7B18%7D%2B%5Cfrac%7B1%7D%7B2%20%5Cpi%20%7D%29%20%7D%20)
and the other part is b-
Answer:
8
Step-by-step explanation:
For a population with mean (μ) = 100 and standard deviation (σ) = 20, the X value corresponding to z = 1.50 is 130.
<h3>What is a z-score?</h3>
A z-score is also referred to as a standard score and it's a measure of the distance between a raw score and the mean, when standard deviation units are used.
<h3>How to determine the value of x?</h3>
In Statistics, the standardized z-score is giving by this formula:
![Z=\frac{\bar{x}\;-\;\mu}{ \sigma }](https://tex.z-dn.net/?f=Z%3D%5Cfrac%7B%5Cbar%7Bx%7D%5C%3B-%5C%3B%5Cmu%7D%7B%20%5Csigma%20%7D)
Making x the subject of formula, we have:
x = Zσ + μ
Substituting the given parameters into the formula, we have;
x = 1.50(20) + 100
x = 30 + 100
x = 130.
Read more on z-scores here: brainly.com/question/4302527
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Complete Question:
For a population with μ= 100 and σ = 20, what is the X value corresponding to z = 1.50?
30
101.5
115
130