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3 years ago

Please help me with this question, and show working out.

Mathematics

1 answer:

Andre45 [30]3 years ago

4 0

<h3>Answer: 2072.4 square cm</h3>

===============================================================

Explanation:

If you used scissors to cut a vertical slice down the lampshade, then it can be unrolled to form a rectangle.

The horizontal portion of this rectangle is the distance around the circle, which is the perimeter of the circle, or the circumference. That's C = 2pi*r. Check out the diagram below to see what I mean.

The diagram shows that the diameter is 20 cm, so the radius is half that at 20/2 = 10 cm.

The circumference is C = 2*pi*r = 2*pi*10 = 20pi cm exactly

The height of the rectangle is the height of the cylinder, which is h = 30 as shown in the diagram.

The area of the rectangle is length*height = (20pi)*(30) = 600pi square cm exactly.

If we were to use something like pi = 3.14, then its approximate area is 600*pi = 600*3.14 = 1884 square cm

Let's bump this up by 10%. To do so, we'll multiply by 1.10

1.10*1884 = 2072.4

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Farmer Green sent his two children out to count the hens and sheep. His daughter counted 40 hens, and his son counted 100 legs.

xz_007 [3.2K]

Answer:

40 hens, 5 sheep

Step-by-step explanation:

40 x 2 = 80 (hens have 2 legs)

100 - 80 = 20 ----> 20 legs left for sheep,, sheep have 4 legs

20/4 = 5 so there are 5 sheep

7 0

3 years ago

Read 2 more answers

What is the solution to the system of equations?<br><br> y = 2x + 4<br> y = -x + 1

den301095 [7]

Step-by-step explanation:

start by setting each equation to each other

$2x + 4 = - x + 1$

first we are going to subtract 2x from both side of the equation

$4 = - 3x + 1$

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$3 = - 3x$

now divide by -3 on both sides

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3 years ago

If the endpoints of the diameter of a circle are (−8, −6) and (−4, −14), what is the standard form equation of the circle?

kondaur [170]

Equation of the circle is $(x+6)^{2}+(y+10)^{2}=20$ .

Solution:

The endpoints of the diameter of a circle are (–8, –6) and (–4, –14).

Center of the circle = Mid point of the diameter

Mid point formula:

$$P(x, y)=\left(\frac{x_{1}+x_{2}}{2}, \frac{y_{1}+y_{2}}{2}\right)$

Here, $x_1=-8, y_1=-6, x_2=-4, y_2=-14$

$$P(x, y) =\left(\frac{-8-4}{2}, \frac{-6-14}{2}\right)$

$$P(x, y) =\left(\frac{-12}{2}, \frac{-20}{2}\right)$

$$P(x, y) =(-6, -10)$

Center of the circle = (–6, –10)

Radius is the distance between center and any endpoint of the diameter.

To calculate the radius using distance formula.

$r=\sqrt{\left(x_{2}-x_{1}\right)^{2}+\left(y_{2}-y_{1}\right)^{2}}$

Here, $x_1=-6, y_1=-10, x_2=-8, y_2=-6$

$r=\sqrt{\left(-8-(-6)\right)^{2}+\left(-6-(-10)}\right)^{2}}$

$r=\sqrt{(-8+6)^{2}+(-6+10)^{2}}$

$r=\sqrt{(-2)^{2}+(4)^{2}}$

$r=\sqrt{20}$ units

The standard form of the equation of a circle is

$(x-a)^{2}+(y-b)^{2}=r^{2}$ , where (a, b) are center and r is the radius.

Here, center = (–6, –10) and $r=\sqrt{20}$

$(x-(-6))^{2}+(y-(-10))^{2}={(\sqrt{20})} ^{2}$

$(x+6)^{2}+(y+10)^{2}=20$

Equation of the circle is $(x+6)^{2}+(y+10)^{2}=20$ .

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3 years ago

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kykrilka [37]

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3 years ago

What is the solution to this system of equations?

antoniya [11.8K]

Answer:

Step-by-step explanation:

Since both equations express y in terms of x we can equate the right sides

3x + 5 = - x + 3 ( add x to both sides )

4x + 5 = 3 ( subtract 5 from both sides )

4x = - 2 ( divide both sides by 4 )

x = - 0.5

substitute x = - 0.5 in either of the 2 equations

using y = - x + 3 then y = 0.5 + 3 = 3.5

solution is (- 0.5, 3.5 ) → c

6 0

3 years ago