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MakcuM [25]
3 years ago
9

Help a friend in need

Mathematics
1 answer:
mafiozo [28]3 years ago
7 0

a) 4.71ft

b) 3.53ft^2

Step-by-step explanation:

Perimeter is 1/2 the circumference

1/2 Circumference = 2*pi*radius

Radius = 1/2 Diameter

Radius = 3/2 = 1.5ft

Circumference = 2*pi*1.5ft = 9.42

1/2 Circumference = 4.71

4.71ft is the perimeter.

The area is 1/2 that of a full circle

A = pi*r^2

A = 3.14*1.5*1.5

A = 7.065ft^2

1/2 A = 3.53ft^2

You might be interested in
Chicken Delight claims that 87% of its orders are delivered within 10 minutes of the time the order is placed. A sample of 80 or
jeka57 [31]

Answer:

There is strong evidence that less than 87% of the orders are delivered in less than 10 minutes.

Decision rule: Reject the null hypothesis if (P-value < level of significance)

Test statistic z=-2.70

Decision: Reject the null hypothesis (0.003<0.010)

Step-by-step explanation:

In this question we have to test an hypothesis.

The null and alternative hypothesis are:

H_0: \pi\geq0.87\\\\H_a:\pi

The significance level is assumed to be 0.01.

The sample of size n=80 gives a proportion of p=61/80=0.7625.

The standard deviation is:

\sigma=\sqrt{\frac{\pi(1-\pi)}{N} }=\sqrt{\frac{0.87*0.13}{80} }=0.0376

The statistic z is then

z=\frac{p-\pi+0.5/N}{\sigma}=\frac{0.7625-0.87+0.5/80}{0.0376} } =\frac{-10125}{0.0376} =-2.70

The P-value is

P(z

The P-value (0.003) is smaller than the significance level (0.010), so the effect is significant. The null hypothesis is rejected.

There is strong evidence that less than 87% of the orders are delivered in less than 10 minutes.

Decision rule: Reject the null hypothesis if (P-value < level of significance)

Test statistic z=-2.70

Decision: Reject the null hypothesis (0.003<0.010)

6 0
3 years ago
Is 30/12 and 40/16 equivalent?
vlabodo [156]
We\ pull\ the\ whole\ numbers\ from\ fractions:\\\\ \frac{30}{12}=2\frac{6}{12}=2\frac{1}{2}\\\\&#10;\frac{40}{16}=2 \frac{8}{16}=2\frac{1}{2}\\\\\&#10;\frac{30}{12}=\frac{40}{16}\\\\They\ are\ equivalent.
6 0
2 years ago
PLZ help picture included
cupoosta [38]

Answer:

4 miles

Step-by-step explanation:

Let

x ----> the time to returned back biking in hours

d ---> the distance in miles

s ---> speed in miles per hour

Remember that

The speed or rate is equal to divide the distance by the time

s=\frac{d}{t}

The distance is equal to multiply the speed by the time

d=st

we know that

18\ min=\frac{18}{60}\ hours

The distance to his friend's house and the distance of return is the same

so

10x=4(x+\frac{18}{60})

solve for x

10x=4x+\frac{18}{15}

subtract 4x both sides

10x-4x=\frac{18}{15}

6x=\frac{18}{15}

x=\frac{1}{5}\ hours

The total distance of the round trip is

y=10x+4x+\frac{18}{15}

substitute the value of x

y=10(\frac{1}{5})+4(\frac{1}{5})+\frac{18}{15}

y=2+2=4\ miles

6 0
3 years ago
How does mathematics connect to the everyday life of an individual?
mr_godi [17]

Answer:

Math is considered to be a part in everyones life, for example, you use math to throw a ball, like the force you use, or the height of the ball. Math is an important concept, and is lingering in our everyday lives, but the reason we take math is to find out of its exsitence, and use it for engineering, etc.

Step-by-step explanation:

5 0
2 years ago
What are the solutions for the following system of equations?
Alenkasestr [34]

Solve for the first variable in one of the equations, then substitute the result into the other equation.

Point Form:

(0,7),(-13,-97)

Equation Form:

x=0,y=7\\x=-13,y=-97

Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :

                    y-(8*x+7)=0

Equation of a Straight Line

Solve   y-8x-7  = 0

"y=mx+b" is the formula of a straight line drawn on Cartesian coordinate system in which "y" is the vertical axis and "x" the horizontal axis.'

n this formula :

y tells us how far up the line goes

x tells us how far along

m is the Slope or Gradient i.e. how steep the line is

b is the Y-intercept i.e. where the line crosses the Y axis

The X and Y intercepts and the Slope are called the line properties. We shall now graph the line  y-8x-7  = 0 and calculate its properties

Graph of a Straight Line :

 

Calculate the Y-Intercept :

Notice that when x = 0 the value of y is 7/1 so this line "cuts" the y axis at y= 7.00000

 y-intercept = 7/1  =  7.00000

Calculate the X-Intercept :

When y = 0 the value of x is 7/-8 Our line therefore "cuts" the x axis at x=-0.87500

 x-intercept = 7/-8  = -0.87500

Calculate the Slope :

Slope is defined as the change in y divided by the change in x. We note that for x=0, the value of y is 7.000 and for x=2.000, the value of y is 23.000. So, for a change of 2.000 in x (The change in x is sometimes referred to as "RUN") we get a change of 23.000 - 7.000 = 16.000 in y. (The change in y is sometimes referred to as "RISE" and the Slope is m = RISE / RUN)

   Slope     = 16.000/2.000 =  8.000

Geometric figure: Straight Line

 Slope = 16.000/2.000 = 8.000

 x-intercept = 7/-8 = -0.87500

 y-intercept = 7/1 = 7.00000

Pull out like factors :

  -x2 - 5x - 7  =   -1 • (x2 + 5x + 7)

Trying to factor by splitting the middle term

2.2     Factoring  x2 + 5x + 7

The first term is,  x2  its coefficient is  1 .

The middle term is,  +5x  its coefficient is  5 .

The last term, "the constant", is  +7

Step-1 : Multiply the coefficient of the first term by the constant   1 • 7 = 7

Step-2 : Find two factors of  7  whose sum equals the coefficient of the middle term, which is   5 .

     -7    +    -1    =    -8

     -1    +    -7    =    -8

     1    +    7    =    8

     7    +    1    =    8

Observation : No two such factors can be found !!

Conclusion : Trinomial can not be factored

Find the Vertex of   y = -x2-5x-7

Parabolas have a highest or a lowest point called the Vertex .   Our parabola opens down and accordingly has a highest point (AKA absolute maximum) .    We know this even before plotting  "y"  because the coefficient of the first term, -1 , is negative (smaller than zero).

Each parabola has a vertical line of symmetry that passes through its vertex. Because of this symmetry, the line of symmetry would, for example, pass through the midpoint of the two  x -intercepts (roots or solutions) of the parabola. That is, if the parabola has indeed two real solutions.

Parabolas can model many real life situations, such as the height above ground, of an object thrown upward, after some period of time. The vertex of the parabola can provide us with information, such as the maximum height that object, thrown upwards, can reach. For this reason we want to be able to find the coordinates of the vertex.

For any parabola,Ax2+Bx+C,the  x -coordinate of the vertex is given by  -B/(2A) . In our case the  x  coordinate is  -2.5000  

Plugging into the parabola formula  -2.5000  for  x  we can calculate the  y -coordinate :

 y = -1.0 * -2.50 * -2.50 - 5.0 * -2.50 - 7.0

or   y = -0.750

Parabola, Graphing Vertex and X-Intercepts :

Root plot for :  y = -x2-5x-7

Axis of Symmetry (dashed)  {x}={-2.50}

Vertex at  {x,y} = {-2.50,-0.75}

Function has no real roots

Solve Quadratic Equation by Completing The Square

3.2     Solving   -x2-5x-7 = 0 by Completing The Square .

Multiply both sides of the equation by  (-1)  to obtain positive coefficient for the first term:

x2+5x+7 = 0  Subtract  7  from both side of the equation :

  x2+5x = -7

Now the clever bit: Take the coefficient of  x , which is  5 , divide by two, giving  5/2 , and finally square it giving  25/4

Add  25/4  to both sides of the equation :

 On the right hand side we have :

  -7  +  25/4    or,  (-7/1)+(25/4)

 The common denominator of the two fractions is  4   Adding  (-28/4)+(25/4)  gives  -3/4

 So adding to both sides we finally get :

  x2+5x+(25/4) = -3/4

Adding  25/4  has completed the left hand side into a perfect square :

  x2+5x+(25/4)  =

  (x+(5/2)) • (x+(5/2))  =

 (x+(5/2))2

Things which are equal to the same thing are also equal to one another. Since

  x2+5x+(25/4) = -3/4 and

  x2+5x+(25/4) = (x+(5/2))2

then, according to the law of transitivity,

  (x+(5/2))2 = -3/4

We'll refer to this Equation as  Eq. #3.2.1  

The Square Root Principle says that When two things are equal, their square roots are equal.

Note that the square root of

  (x+(5/2))2   is

  (x+(5/2))2/2 =

 (x+(5/2))1 =

  x+(5/2)

6 0
2 years ago
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