To apply the SAS (Side-Angle-Side) Congruence Theorem, two sides of one triangle must be equal to two sides of the other triangle, and the angle included between the two sides must also be equal.
To determine the correct value of
Without the specific side lengths, angles, and the exact configurations of the triangles given, I can't calculate a specific value for
To conclude:
- If the included angle and the lengths of two sides can be made equal by setting
to a specific value, then that value would be your answer. - If no such value allows for equality with respect to the sides and angle, then the answer is "There is no value of
that will allow us to prove that these triangles are congruent."
Please refer to the specific problem details to see if any of the values (21, 13, 19) can satisfy the condition for congruence.