The uppercase letters are the angles, while the lowercase letters are the sides. We have side 'a' opposite angle A, side b opposite angle B, side c opposite angle C.
We have this given info:
Let's use the law of sines to find angle B
sin(B)/b = sin(A)/a
sin(B)/25.5 = sin(25)/13.2
sin(B) = 25.5*sin(25)/13.2
sin(B) = 0.81642164
B = arcsin(0.81642164) or B = 180 - arcsin(0.81642164)
B = 54.72817392 or B = 180 - 54.72817392
B = 54.72817392 or B = 125.27182608
When rounded to the nearest whole degree, we get B = 55 or B = 125.
However, I'll use the slightly more accurate values of B for the next two sections.
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Let's consider the case that B = 54.72817392
This would have to mean
A+B+C = 180
C = 180-A-B
C = 180-25-54.72817392
C = 100.27182608 which rounds to C = 100
Through the law of sines we can say
c/sin(C) = a/sin(A)
c = sin(C)*a/sin(A)
c = sin(100.2718 2608)*13.2/sin(25)
c = 30.73327084 which rounds to c = 30.7
One solution is
A = 25, B = 55, C = 100
a = 13.2, b = 25.5, c = 30.7
As you can probably guess, the phrasing "solve the triangle" means find all sides and angle measures.
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Now we'll consider the case that B = 125.27182608
We follow the same steps as the previous section
A+B+C = 180
C = 180-A-B
C = 180-25-125.27182608
C = 29.72817392 which rounds to C = 30
and
c/sin(C) = a/sin(A)
c = sin(C)*a/sin(A)
c = sin(29.72817392)*13.2/sin(25)
c = 15.48842618 which rounds to c = 15.5
The other solution is
A = 25, B = 125, C = 30
a = 13.2, b = 25.5, c = 15.5
Check out the diagrams below.