The Ambiguous SSA Triangle – Given an Obtuse Angle


When given a SSA triangle with sides \(a\), \(b\) and \(\angle A\), which is obtuse, two cases are possible.

Case 1: \(a \le b\)

If the side opposite the given angle is less than or equal to the other given side \((a \le b)\), then there is no solution since no triangle is possible.



Case 2: \(a > b\)

If the side opposite the given angle is greater than the other given side \((a > b)\), then exactly one triangle is defined, so there is one solution.



 

 Key Lesson Marker



Given a SSA triangle such as \(\triangle ABC\), and angle \(A\) is obtuse:

Situation  Number of solutions
\(a \le b\)
No solution
\(a > b\)
One solution