In this case we know the three sides of the triangle, then this is a SSS triangle (Side Side Side). To solve this case, first we must use the Law of Cosines, applied to the opposite side to the angle we want to find.
We want to find angle W, and its opposite side is XV, then we apply the Law of Cosines to the side XV:
XV^2=XW^2+WV^2-2(XW)(WV)cos W
Replacing the known values:
116^2=96^2+89^2-2(96)(89)cos W
Solving for W
13,456=9,216+7,921-17,088 cos W
13,456=17,137-17,088 cos W
13,456-17,137=17,137-17,088 cos W-17,137
-3,681=-17,088 cos W
(-3,681)/(-17,088)=(-17,088 cos W)/(-17,088)
0.215414326=cos W
cos W = 0.215414326
Solving for W:
W= cos^(-1) 0.215414326
Using the calculator:
W=77.56016397°
Rounded to one decimal place:
W=77.6°
Answer: Third option 77.6°
Answer:
Solution of a System. In general, a solution of a system in two variables is an ordered pair that makes BOTH equations true. In other words, it is where the two graphs intersect, what they have in common. So if an ordered pair is a solution to one equation, but not the other, then it is NOT a solution to the system.
I thought i know but i don’t sorry
Answer:
or 
Step-by-step explanation:
We use casework on when 
and when 
.
For the first case, , we add 9 to both sides to get
.
Dividing both sides by 3 gives
For the second case, , we add 9 to both sides to get
.
Dividing both sides by 3 gives
.
Checking both cases, we plug in 
and .
For the first case, we have 
, which satisfies the equation.
For the second case, we have 
, which also satisfies the equation.
This gives us two solutions to the equation; and .
