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Masja [62]
3 years ago
11

Does anyone know how to do this ??? -view attachment

Mathematics
1 answer:
cricket20 [7]3 years ago
8 0

As soon as I read this, the words "law of cosines" popped
into my head.  I don't have a good intuitive feeling for the
law of cosines, but I went and looked it up (you probably
could have done that), and I found that it's exactly what
you need for this problem.

The "law of cosines" relates the lengths of the sides of any
triangle to the cosine of one of its angles ... just what we need,
since we know all the sides, and we want to find one of the angles.

To find angle-B, the law of cosines says

       b² = a² + c² - 2 a c cosine(B)

B  =  angle-B
b  =  the side opposite angle-B = 1.4
a, c = the other 2 sides = 1 and 1.9

                  (1.4)² = (1)² + (1.9)² - (2 x 1 x 1.9) cos(B)

                 1.96  =  (1) + (3.61)  -  (3.8) cos(B)

Add  3.8 cos(B)  from each side:

                 1.96 + 3.8 cos(B) = 4.61

Subtract  1.96  from each side:

                             3.8 cos(B) =  2.65

Divide each side by  3.8 :

                                  cos(B)  =  0.69737  (rounded)

Whipping out the
trusty calculator:
                                 B  = the angle whose cosine is 0.69737

                                      =  45.784° .

Now, for the first time, I'll take a deep breath, then hold it
while I look back at the question and see whether this is
anywhere near one of the choices ...

By gosh !  Choice 'B' is  45.8° !                    yay !
I'll bet that's it !

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just olya [345]
Multiply first example by 3 and subtract by second example, you will get the following:

3*(5x + 2y) = 3*22   =>  3*5x + 3*2y = 66      =>  15x + 6y = 66
now subtraction:
(15x + 6y) - (-2x + 6y) = 66 - 3
15x + 6y + 2x - 6y = 63
15x + 2x + 6y - 6y = 63
17x = 63
x = 63/17 ≈ 3.705..... and as it says to round to the nearest tenth our answer would be: x = 3.7
8 0
3 years ago
What is the solution to the system of equations below?<br>2x+3y = 17<br>3x+6y= 30​
brilliants [131]

Answer:

<h2>x = 4, y = 3 → (4, 3)</h2>

Step-by-step explanation:

\left\{\begin{array}{ccc}2x+3y=17&\text{multiply both sides by (-2)}\\3x+6y=30\end{array}\right\\\underline{+\left\{\begin{array}{ccc}-4x-6y=-34\\3x+6y=30\end{array}\right}\qquad\text{add both sides of the equations}\\.\qquad-x=-4\qquad\text{change the signs}\\.\qquad x=4\\\\\text{put the value of x to the first equation:}\\\\2(4)+3y=17\\8+3y=17\qquad\text{subtract 8 from both sides}\\3y=9\qquad\text{divide both sides by 3}\\y=3

5 0
3 years ago
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Answer:

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Step-by-step explanation:

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8 0
2 years ago
Two sides of a triangle measure 9 cm and 23 cm. Which could be the measure of the third side of the triangle?
Verizon [17]
Hello,

Let's be x the length of the 3 side (9,x,23) ==>x>0

Using inequality triangular:

9<x+23==>x>9-23==>x>-14 (done)
x<9+23==>x<32
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3 years ago
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HELP FAST PLEASE! ILL GIVE 20 POINTS PLUS BRAINLIEST!!!!
pav-90 [236]

Answer:

  see below

Step-by-step explanation:

The recursive function tells you the first term is 1. That is the meaning of ...

  a_1=1

It also tells you that to find the next term, you multiply this term by 1/2:

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Then the first three terms are ...

  1, 1/2, 1/4

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