Answer:
Let we have two sides 'a' and 'b' and an angle α, β opposite 'a' and 'b'.
Then the law of sines states that:
=
For triangle angles, the sine is always positive.
The expression may give value exactly equal to 1 which means α=90°, therefore the question determines exactly one triangle that is the the right triangle.
For sinα<1, there are two triangle angles with the principal angle in the first quadrant and the other in the second quadrant.
sinβ=0 is the special case and called degenerate triangle.
Step-by-step explanation: