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3 years ago

The circle has a radius of 11 cm about how many square centimeters of paper does Mary need for her circle

Mathematics

1 answer:

Ierofanga [76]3 years ago

5 0

Answer:

I think the answer would be 380.13

Step-by-step explanation:

Please let me know if i am wrong

11*2

radius is half the diameter of a circle

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Today, you earn a salary of $28,000. what will be your annual salary twelve years from now if you earn annual raises of 2.6 perc

Debora [2.8K]

Salary after 12 years = $28,000(1+0.026)^12 =$38100.12

8 0

3 years ago

Number 15. Find the equation of the line that passes through (3,-1) and is perpendicular to the line that passes through (-5, 2)

MArishka [77]

For lines to be perpendicular their slopes must be negative reciprocals of one another, mathematically:

m1*m2=-1

So we first need to find the slope of the reference line.

m=(y2-y1)/(x2-x1)=(7-2)/(-1--5)=5/4

So the perpendicular line will have a slope of:

5m/4=-1

m=-4/5

So our perpendicular line so far is:

y=-4x/5+b, now we can use point (3,-1) to solve for the y-intercept, "b"

-1=-4(3)/5+b

-1=-12/5+b

-5/5+12/5=b

7/5=b

So the line is:

y=-4x/5+7/5 or more neatly

y=(-4x+7)/5

y=-0.8x+1.4

3 0

3 years ago

The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took these 100 customer

AlladinOne [14]

Answer:

$4-2.326\frac{1}{\sqrt{100}}=3.767$

$4+2.326\frac{1}{\sqrt{100}}=4.233$

So on this case the 98% confidence interval would be given by (3.767;4.233)

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X=4$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=1$ represent the population standard deviation

n=100 represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.98 or 98%, the value of $\alpha=0.02$ and $\alpha/2 =0.01$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.01,0,1)".And we see that $z_{\alpha/2}=2.326$

Now we have everything in order to replace into formula (1):

$4-2.326\frac{1}{\sqrt{100}}=3.767$

$4+2.326\frac{1}{\sqrt{100}}=4.233$

So on this case the 98% confidence interval would be given by (3.767;4.233)

4 0

3 years ago

Part A

masya89 [10]

Answer:

Part A) The area of triangle i is $3\ cm^{2}$

Part B) The total area of triangles i and ii is $6\ cm^{2}$

Part C) The area of rectangle i is $20\ cm^{2}$

Part D) The area of rectangle ii is $32\ cm^{2}$

Part E) The total area of rectangles i and iii is $40\ cm^{2}$

Part F) The total area of all the rectangles is $72\ cm^{2}$

Part G) To find the surface area of the prism, we need to know only the area of triangle i and the area of rectangle i and the area of rectangle ii, because the area of triangle ii is equal to the area of triangle i and the area of rectangle iii is equal to the area of rectangle i

Part H) The surface area of the prism is $78\ cm^{2}$

Part I) The statement is false

Part J) The statement is true

Step-by-step explanation:

Part A) What is the area of triangle i?

we know that

The area of a triangle is equal to

$A=\frac{1}{2} (b)(h)$

we have

$b=4\ cm$

$h=1.5\ cm$

substitute

$A=\frac{1}{2} (4)(1.5)$

$Ai=3\ cm^{2}$

Part B) Triangles i and ii are congruent (of the same size and shape). What is the total area of triangles i and ii?

we know that

If Triangles i and ii are congruent

then

Their areas are equal

$Aii=Ai$

The area of triangle ii is equal to

$Aii=3\ cm^{2}$

The total area of triangles i and ii is equal to

$A=Ai+Aii$

substitute the values

$A=3+3=6\ cm^{2}$

Part C) What is the area of rectangle i?

we know that

The area of a rectangle is equal to

$A=(b)(h)$

we have

$b=2.5\ cm$

$h=8\ cm$

substitute

$Ai=(2.5)(8)$

$Ai=20\ cm^{2}$

Part D) What is the area of rectangle ii?

we know that

The area of a rectangle is equal to

$A=(b)(h)$

we have

$b=4\ cm$

$h=8\ cm$

substitute

$Aii=(4)(8)$

$Aii=32\ cm^{2}$

Part E) Rectangles i and iii have the same size and shape. What is the total area of rectangles i and iii?

we know that

Rectangles i and iii are congruent (have the same size and shape)

If rectangles i and iii are congruent

then

Their areas are equal

$Aiii=Ai$

The area of rectangle iii is equal to

$Aiii=20\ cm^{2}$

The total area of rectangles i and iii is equal to

$A=Ai+Aiii$

substitute the values

$A=20+20=40\ cm^{2}$

Part F) What is the total area of all the rectangles?

we know that

The total area of all the rectangles is

$At=Ai+Aii+Aiii$

substitute the values

$At=20+32+20=72\ cm^{2}$

Part G) What areas do you need to know to find the surface area of the prism?

To find the surface area of the prism, we need to know only the area of triangle i and the area of rectangle i and the area of rectangle ii, because the area of triangle ii is equal to the area of triangle i and the area of rectangle iii is equal to the area of rectangle i

Part H) What is the surface area of the prism? Show your calculation

we know that

The surface area of the prism is equal to the area of all the faces of the prism

The surface area of the prism is two times the area of triangle i plus two times the area of rectangle i plus the area of rectangle ii

$SA=2(3)+2(20)+32=78\ cm^{2}$

Part I) Read this statement: “If you multiply the area of one rectangle in the figure by 3, you’ll get the total area of the rectangles.” Is this statement true or false? Why?

The statement is false

Because, the three rectangles are not congruent

The total area of the rectangles is $72\ cm^{2}$ and if you multiply the area of one rectangle by 3 you will get $20*3=60\ cm^{2}$

$72\ cm^{2}\neq 60\ cm^{2}$

Part J) Read this statement: “If you multiply the area of one triangle in the figure by 2, you’ll get the total area of the triangles.” Is this statement true or false? Why?

The statement is true

Because, the triangles are congruent

8 0

3 years ago

JUST THE FIRST ONE EASY PLS ASAP

Sladkaya [172]

Answer:

<h2>For the first triangle, <u>x equals 22cm.</u></h2>

Here's how:-

x is the altitude or height of the triangle. To find it, we can use the Pythagoras theorem:-

$altitude^{2} + base^{2} = hypotenuse^{2}$