Which value of n makes this equation true?

351 students in 27 classes _____ students in each class

77julia77 [94]

Answer:

13

Step-by-step explanation:

351 divided by 27 = 13

7 0

2 years ago

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A wire b units long is cut into two pieces. One piece is bent into an equilateral triangle and the other is bent into a circle.

mezya [45]

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= $\frac{1}{2}sin60^{o}side*side= \frac{1}{2} \frac{ \sqrt{3} }{2} (\frac{b-x}{3}) ^{2}= \frac{ \sqrt{3} }{36}(b-x)^{2}$
A= $\frac{ \sqrt{3} }{36}(b-x)^{2}=\frac{ \sqrt{3} }{36}( b^{2}-2bx+ x^{2} )=\frac{ \sqrt{3} }{36}b^{2}-\frac{ \sqrt{3} }{18}bx+ \frac{ \sqrt{3} }{36}x^{2}$

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.

$2 \pi r=x$

so $r= \frac{x}{2 \pi }$

Area of circle = $\pi r^{2}= \pi ( \frac{x}{2 \pi } )^{2} = \frac{ \pi }{ 4 \pi ^{2} }* x^{2} = \frac{1}{4 \pi } x^{2}$

4. Let f(x)= $\frac{ \sqrt{3} }{36}b^{2}-\frac{ \sqrt{3} }{18}bx+ \frac{ \sqrt{3} }{36}x^{2}+\frac{1}{4 \pi } x^{2}$

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)= $\frac{ -\sqrt{3} }{18}b+ \frac{ \sqrt{3} }{18}x+\frac{1}{2 \pi } x$ =0

$\frac{ -\sqrt{3} }{18}b+ \frac{ \sqrt{3} }{18}x+\frac{1}{2 \pi } x=0$

$(\frac{ \sqrt{3} }{18}+\frac{1}{2 \pi }) x=\frac{ \sqrt{3} }{18}b$

$x= \frac{\frac{ \sqrt{3} }{18}b}{(\frac{ \sqrt{3} }{18}+\frac{1}{2 \pi }) }$

6. So one part is $\frac{\frac{ \sqrt{3} }{18}b}{(\frac{ \sqrt{3} }{18}+\frac{1}{2 \pi }) }$ and the other part is b- $\frac{\frac{ \sqrt{3} }{18}b}{(\frac{ \sqrt{3} }{18}+\frac{1}{2 \pi }) }$

4 0

3 years ago

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The data below are the monthly average high temperatures for New York City. What is the five-number summary? 40, 40, 48, 61, 72,

yawa3891 [41]

Answer:

B) Sample minimum: 40, Sample maximum: 84

Q1: 45, Median: 63, Q3: 77

Step-by-step explanation:

The first step is to write the temperatures in crescent order:

40, 40, 42, 48, 54, 61, 65, 72, 76, 78, 84, 84,

The sample minimum is the lowest value = 40

The sample maximum is the highest value = 84.

Since there are 12 numbers, the sample median is the average between the 6th and 7th terms:

$M = \frac{61+65}{2}\\ M=63$

The first quartile is the average between the 3rd and 4th terms:

$Q_1 = \frac{42+48}{2}\\ Q_1=45$

The third quartile is the average between the 9th and 10th terms:

$Q_3 = \frac{76+78}{2}\\ Q_3=77$

Therefore, the answer is:

B) Sample minimum: 40, Sample maximum: 84

Q1: 45, Median: 63, Q3: 77

8 0

2 years ago

Angle W and angle X are congruent. If their sum is 121 degrees, what is the measure of angle X?

____ [38]

Angle X = 60.5 degrees

6 0

3 years ago

1. How can you tell that a point on the graph is a maximum or minimum?

spin [16.1K]

Answer:

1) To see whether it is a maximum or a minimum, in this case we can simply look at the graph. f(x) is a parabola, and we can see that the turning point is a minimum. By finding the value of x where the derivative is 0, then, we have discovered that the vertex of the parabola is at (3, −4).

2

6 0

3 years ago