Question

1. when triangle abc is reflected across line ab, the image is triangle abd. why is angle acd congruent to angle adb? (lesson 2 - 1) a corresponding parts of congruent figures are congruent. b congruent parts of congruent figures are corresponding. c segment ab is a perpendicular bisector of segment dc. d an isosceles triangle has a pair of congruent angles.

Explanation:

When a triangle ABC is reflected across line AB to get triangle ABD, the two triangles are congruent. By the property of congruent figures, corresponding parts of congruent figures are congruent. Angle ACD and angle ADB are corresponding angles of congruent triangles △ABC and △ABD.

Answer:

A. Corresponding parts of congruent figures are congruent.