Problem
GEO-B1-M02-P002 A Side and Two Angles
#2
★☆☆☆☆ Level 1 of 5
In triangles \(ABC\) and \(A_1B_1C_1\), suppose \(AB=A_1B_1\), \(\angle A=\angle A_1\), and \(\angle B=\angle B_1\). Prove that \(AC=A_1C_1\).
Side \(AB\) is adjacent to angles \(A\) and \(B\).
A side and its two adjacent angles are respectively equal in the two triangles. Hence the triangles are congruent by ASA. Therefore the corresponding sides \(AC\) and \(A_1C_1\) are equal.
Emphasise the order of corresponding vertices.