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Luden [163]
3 years ago
5

The cover of a rectangular book has an area of 20 inches . If the books length is 3 times as long as it’s width explain how to f

ind the exact perimeter of the book cover.
Mathematics
1 answer:
zloy xaker [14]3 years ago
6 0

Answer:

Step-by-step explanation:

If the books length (L) is three times as long as the width (W), the equation for area is this:

L · W = 20 inches,

3W · W = 20 inches -  substituting L for 3W

So then the books perimeter is

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Shalnov [3]

Answer:

#3

Step-by-step explanation:

5 0
3 years ago
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Find the dimensions of the open rectangular box of maximum volume that can be made from a sheet of cardboard 21 in. by 12 in. by
a_sh-v [17]

Answer:

Dimension of the box is 16.1\times 7.1\times 2.45

The volume of the box is 280.05 in³.

Step-by-step explanation:          

Given : The open rectangular box of maximum volume that can be made from a sheet of cardboard 21 in. by 12 in. by cutting congruent squares from the corners and folding up the sides.

To find : The dimensions and the volume of the box?

Solution :

Let h be the height of the box which is the side length of a corner square.

According to question,

A sheet of cardboard 21 in. by 12 in. by cutting congruent squares from the corners and folding up the sides.

The length of the box is L=21-2h

The width of the box is W=12-2h

The volume of the box is V=L\times W\times H

V=(21-2h)\times (12-2h)\times h

V=(21-2h)\times (12h-2h^2)

V=252h-42h^2-24h^2+4h^3

V=4h^3-66h^2+252h

To maximize the volume we find derivative of volume and put it to zero.

V'=12h^2-132h+252

0=12h^2-132h+252

Solving by quadratic formula,

h=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

h=\frac{-(-132)\pm\sqrt{132^2-4(12)(252)}}{2(12)}

h=\frac{132\pm72.99}{24}

h=2.45,8.54

Now, substitute the value of h in the volume,

V=4h^3-66h^2+252h

When, h=2.45

V=4(2.45)^3-66(2.45)^2+252(2.45)

V\approx 280.05

When, h=8.54

V=4(8.54)^3-66(8.54)^2+252(8.54)

V\approx -170.06

Rejecting the negative volume as it is not possible.

Therefore, The volume of the box is 280.05 in³.

The dimension of the box is

The height of the box is h=2.45

The length of the box is L=21-2(2.45)=16.1

The width of the box is W=12-2(2.45)=7.1

So, Dimension of the box is 16.1\times 7.1\times 2.45

6 0
3 years ago
Homer and Bart plan to buy one computer for $499.00 strictly for gaming
kati45 [8]

Answer:

Part A: T(x) = $49.99x + $499.00

Part B: $748.95

Part C: T(x) = $49.99x + $24.99y + $499.00

Part D: $773.93

Step-by-step explanation:

Part A:

Let x represent the amount of games bought. Let T(x) represent total cost.

T(x) = $49.99x + $499.00

Part B:

T(x) = $49.99(5) + $499.00

T(x) = $249.95 + $499.00

T(x) = $748.95

Part C:

Let y represent the amount of controllers bought.

T(x) = $49.99x + $24.99y + $499.00

Part D:

T(x) = $49.99(4) + $24.99(3) + $499.00

T(x) = $199.96‬ + $74.97 + $499.00

T(x) = $773.93

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3 years ago
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Delicious77 [7]

Answer:

-16

Step-by-step explanation:

8 0
3 years ago
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mart [117]

Answer:

180-43

Step-by-step explanation:

43 and x are supplementary which means they both should equal 180

8 0
2 years ago
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