Question

What additional information can be used to prove ΔDSB ≅ ΔTSR by SAS?

Answer 1

Please find the attached file for a proper understanding of the question given here. The diagram in the file attached is the complete accompanying diagram of the question.

As per that diagram, $RS\cong SB$ (which is given)

and we know that $\angle DSB\cong \angle RST$ (vertically opposite angles).

Thus, the only way ΔDSB ≅ ΔTSR by SAS is when $DS\cong ST$ as indicated in the diagram.

Thus, $DS\cong ST$ is the correct answer.

Answer 2

I believe the correct answer is
ST≈SD