7. one triangle
8. two triangles
Step-by-step explanation:
When you are given two sides and one of the opposite angles, you can make a determination as follows:
If the given angle is opposite the longest given side, there is one solution.If the given angle is opposite the shortest given side, there may be 0, 1, or 2 solutions.
For the latter case, the possibilities for sides b, c, and angle C are ...
C > 90° . . . . . . . . no solution
(b/c)sin(C) > 1 . . . no solution
(b/c)sin(C) = 1 . . . 1 solution
(b/c)sin(C) < 1 . . . 2 solutions
(The expression (b/c)sin(C) gives sin(B), so the value must lie within the range of the sine function in order for there to be any solution.)
7. The given angle is opposite the longest given side. There is one solution.
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8. The given angle is opposite the shortest given side, so we compute
(b/c)sin(C) = (34/28)sin(20°) ≈ 0.41
This is less than 1, so there are two solutions.