What single transformation is required to map one of these congruent triangles onto the other?
reflection
rotation
translation
dilation

Reflection is required to map one of these congruent triangles onto the other.

Option A

Explanation:

Congruent triangles are two triangles that will have the same three sides, line segments, and angles. Congruence transformation is transforming triangles that does not change its sides, shapes, line segments and angles.

The congruence is obtained when two triangles move or dilated and both the triangles stay the same i.e. each triangle should fit another triangle exactly. The three congruence transformation types: Rotation (turn) - changing the axis of the triangle, Translation (slide) -  moving the triangle, and reflection (flip) - the mirror image of the triangle.