Mathematics, 25.09.2019 05:40 jdkrisdaimcc11

Nδdef, de = 11, ef = 9, and angle e = 140°. which equation correctly uses the law of cosines to solve for the third side?

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Answer from: rebeccacruzz2017

e^2=11^2+9^2-2*11*9*cos(140^o)

Step-by-step explanation:

Please find the attachment.

We have been given that in ΔDEF, DE = 11, EF = 9, and angle E = 140°. We are asked to determine the equation that can be used to find the length of third side using law of cosines.

We can use Law of cosines to solve for a side of triangle, when we are given other two sides of the triangle and angle corresponding the side we need to figure out.

c^2=a^2+b^2-2ac*cos(c)

We can see from our attachment that e is side corresponding to angle 140 degrees, so to find the length of we can set an equation as:

e^2=f^2+d^2-2fd*cos(e)

Upon substituting our given values we will get,

e^2=11^2+9^2-2*11*9*cos(140^o)

Therefore, the equation e^2=11^2+9^2-2*11*9*cos(140^o) can be used to find the length of third side.

Let us solve for third side.

e^2=121+81-198*cos(140^o)

e^2=121+81-198*(-0.766044443119)

e^2=121+81+151.676799737562

e^2=353.676799737562

Let us take square root of both sides of our equation.

$e=\sqrt{353.676799737562}$

$e=18.806\approx 18.81$

Therefore, the length of 3rd side of triangle DEF is 18.81.

Nδdef, de = 11, ef = 9, and angle e = 140°. which equation correctly uses the law of cosines to solv

Answer from: impura12713

e2 = 112 + 92 − 2(11)(9)cos(140°)

i did the assignment i hope this helps some! :)

Step-by-step explanation:

Triangle D E F is shown. Angle D E F is 140 degrees. The length of D E is 11, the length of E F is 9, and the length of D F is e.

In ΔDEF, DE = 11, EF = 9, and angle E = 140°.

Which equation correctly uses the law of cosines to solve for the third side?

e2 = 112 + 92 − 2(11)(9)cos(140°)

112 = e2 + 92 − 2e(9)cos(140°)

92 = e2 + 112 − 2e(11)cos(140°)

e = 11 + 9 − 2(11)(9)cos(140°)

Answer from: Quest

i think it would be 43 movies that would have to be watched.

step-by-step explanation:

think about it. for the second plan, every month is 8 dollars. 8 x 12= 96. so thats the number for the second plan. now for the first plan, its annual meaning you have to pay 10 dollars every year. so now you have to get an equivalent amount of 86 since 96-10=86. 86 divided by 2 since every movie costs 2$ then you would have to watch 43 movies a year to get the same as the second plan. i really hoped this . have a wonderful day as well!

Answer from: Quest

if x = 1, then the answer is 3.5

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Nδdef, de = 11, ef = 9, and angle e = 140°. which equation correctly uses the law of cosines to solv...