Jennifer knows that at least one of Franklin's measures of the angles of the triangle is incorrect because the sum of the inner angles of a triangle is equal to 180°.
When you add the shown measures you get:
37° + 97° + 134° = 268° ≠ 180°, which makes this an impossible triangle.
Explanation 2:
Jennifer also can know that either the measure 97° or 134° (or even both) is incorrect.
This is so because the addition of those two measures is
97° + 134° = 231°
Since 231° > 180° those measures cannot be correct because the sum of two angles of an triangle has to be less than 180°, given that when they are summed to the other angle the sum has to be 180°.
