Question

which rigid transformation would map △abc to △edc? a rotation about point c a rotation about point b a reflection across the line containing cb a reflection across the line containing ac

Explanation:

Step1: Analyze rotation about point C

If we rotate $\triangle ABC$ about point $C$, we can align the sides and angles to match $\triangle EDC$. Point - C is a common vertex for both triangles. A rotation about point C can map the corresponding sides and angles correctly.

Step2: Analyze rotation about point B

Rotating about point B will not map $\triangle ABC$ to $\triangle EDC$ as the orientation and position of the triangles relative to point B do not allow for such a mapping.

Step3: Analyze reflection across line containing $\overline{CB}$

A reflection across the line containing $\overline{CB}$ will not map $\triangle ABC$ to $\triangle EDC$ as the orientation of the triangles will be wrong for a reflection across this line.

Step4: Analyze reflection across line containing $\overline{AC}$

A reflection across the line containing $\overline{AC}$ will not map $\triangle ABC$ to $\triangle EDC$ as it will not align the sides and angles correctly.

Answer:

a rotation about point C