1. The problem asks to select the shortcut to prove that two given triangles are similar. 2. The triangles are right-angled and share a common side, with one right angle in each triangle. 3. Similarity shortcuts include: - Angle-Angle (AA): Two angles of one triangle are congruent to two angles of another. - Angle-Side-Angle (ASA): Two angles and the included side are congruent. - Side-Angle-Side (SAS): Two sides and the included angle are congruent. - Side-Side-Side (SSS): All three sides are proportional. 4. Since both triangles have a right angle, that gives one pair of equal angles. 5. The triangles share a common angle where they meet (the angle between the common side and the hypotenuse), so the second pair of angles are equal. 6. By the Angle-Angle (AA) similarity criterion, two angles of one triangle are equal to two angles of the other triangle, so the triangles are similar. 7. Therefore, the correct shortcut is **Angle-Angle Similarity**. Final answer: A. Angle-Angle Similarity