The Law of Cosines features the 3 side lengths of a triangle, plus the measure of the angle opposite one of those sides.
We want angle x, which is opposite the side of length 39.
Then: a^2 = b^2 - 2ab cos C becomes 39^2 = 36^2 + 59^2 - 2(36)(59)cos x
or 1521 = 3481 + 1296 - 2(36)(59) cos x
Subtract (3481+1296) from both sides: 1521 - 4777 = -4248cos x
-3256 = -4248cos x
-3256
Then: cosx = --------------- = 0.766
-4248
Solving for x: x = arccos -0.766 = 0.698 radian, or 40 degrees (answer)
Answer:
○B. 
Step-by-step explanation:
Trigonometric Identities
<u>Radius Formula</u>
![{[-\sqrt{15}]}^{2} + {[-\sqrt{10}]}^{2} = {r}^{2} → 15 + 10 = {r}^{2} → 25 = {r}^{2}\\ \\ 5 = r](https://tex.z-dn.net/?f=%7B%5B-%5Csqrt%7B15%7D%5D%7D%5E%7B2%7D%20%2B%20%7B%5B-%5Csqrt%7B10%7D%5D%7D%5E%7B2%7D%20%3D%20%7Br%7D%5E%7B2%7D%20%E2%86%92%2015%20%2B%2010%20%3D%20%7Br%7D%5E%7B2%7D%20%E2%86%92%2025%20%3D%20%7Br%7D%5E%7B2%7D%5C%5C%20%5C%5C%205%20%3D%20r)
* Since we are talking about radii, we only want the NON-NEGATIVE root.
In this case, we will not be using the radius in our ratio, according to the trigonometric identity above because we are using the <em>tangent</em><em> </em>ratio:
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She will have $500 in 5 days because when she takes out the 20 every week she will have had $100 so to make $500 she will have to have made 5 $100
There are 8 fl ounces in 1 cup.
Divide 128 by 8.
16 cups
So you know the whole line is XZ which is 83.Then you find out it is in two parts so that is XY and YZ which are 11 and 4c. You can make the equation:
11+4c=83
4c=72
c=18
c=18 and YZ=72
