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Inga [223]
3 years ago
15

Explain why the equation 2L + 2W = 4(L - W + 7) is true for the rectangle

Mathematics
2 answers:
guapka [62]3 years ago
7 0
<span> you can find the perimeter of rectangle if you subtract the width from the length, add 7 inches, and multiply the result by 4. b.Explain the equation 2L +2w=4(L-w+7)</span>
nikklg [1K]3 years ago
6 0
P = 2W +2L step is keep 2L in one side of equation , and move every thing else to the other side. In moving any quantity from one side to other, change the sign. ( equivalent of adding or subtracting equal                                                                                                  quantity from both sides of equation). 2L = P - 2W divide both sides by 2:  L = p/2 - w  Step is the same as solving  X in equation of  8 = 2X + 16 2X = 8 -16 = 8   X =4 . But, here you solve one variable in terms of other variables. <span>9/9/2013 </span>| <span>Parviz F.

</span>
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What two numbers create a product of -12 and a sum of 4?
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-2 and 6

Step-by-step explanation:

-2+6=4

-2×6=-12

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Pick a two-digit number greater than 25. Rewrite your two-digit number as a difference of two numbers. Show how to use the ident
e-lub [12.9K]

Answer:

Step-by-step explanation:

32²=(40-8)²

=40²-2(40)(8)+8²

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2 years ago
I need help with questions #7 and #8 plz
katen-ka-za [31]

Answer:

7. A = 40.8 deg; B = 60.6 deg; C = 78.6 deg

8. A = 20.7 deg; B = 127.2 deg; C = 32.1 deg

Step-by-step explanation:

Law of Cosines

c^2 = a^2 + b^2 - 2ab \cos C

You know the lengths of the sides, so you know a, b, and c. You can use the law of cosines to find C, the measure of angle C.

Then you can use the law of cosines again for each of the other angles. An easier way to solve for angles A and B is, after solving for C with the law of cosines, solve for either A or B with the law of sines and solve for the last angle by the fact that the sum of the measures of the angles of a triangle is 180 deg.

7.

We use the law of cosines to find C.

18^2 = 12^2 + 16^2 - 2(12)(16) \cos C

324 = 144 + 256 - 384 \cos C

-384 \cos C = -76

\cos C = 0.2

C = \cos^{-1} 0.2

C = 78.6^\circ

Now we use the law of sines to find angle A.

Law of Sines

\dfrac{a}{\sin A} = \dfrac{b}{\sin B} = \dfrac{c}{\sin C}

We know c and C. We can solve for a.

\dfrac{a}{\sin A} = \dfrac{c}{\sin C}

\dfrac{12}{\sin A} = \dfrac{18}{\sin 78.6^\circ}

Cross multiply.

18 \sin A = 12 \sin 78.6^\circ

\sin A = \dfrac{12 \sin 78.6^\circ}{18}

\sin A = 0.6535

A = \sin^{-1} 0.6535

A = 40.8^\circ

To find B, we use

m<A + m<B + m<C = 180

40.8 + m<B + 78.6 = 180

m<B = 60.6 deg

8.

I'll use the law of cosines 3 times here to solve for all the angles.

Law of Cosines

a^2 = b^2 + c^2 - 2bc \cos A

b^2 = a^2 + c^2 - 2ac \cos B

c^2 = a^2 + b^2 - 2ab \cos C

Find angle A:

a^2 = b^2 + c^2 - 2bc \cos A

8^2 = 18^2 + 12^2 - 2(18)(12) \cos A

64 = 468 - 432 \cos A

\cos A = 0.9352

A = 20.7^\circ

Find angle B:

b^2 = a^2 + c^2 - 2ac \cos B

18^2 = 8^2 + 12^2 - 2(8)(12) \cos B

324 = 208 - 192 \cos A

\cos B = -0.6042

B = 127.2^\circ

Find angle C:

c^2 = a^2 + b^2 - 2ab \cos C

12^2 = 8^2 + 18^2 - 2(8)(18) \cos B

144 = 388 - 288 \cos A

\cos C = 0.8472

C = 32.1^\circ

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2 years ago
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Step-by-step explanation:

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