What is the most obvious property you can use to prove that both △QRT and △SRT are congruent?

Explanation

Given from the tick marks

• \( \overline {QR} \) = \( \overline{RS} \) (double tick marks)

• \( \overline{QT} \) = \( \overline{TS} \) (single tick marks)

• \( \overline{RT} \) is common to both triangles (shared side)

So each triangle has:

• Two sides that match the other triangle

• The included angle between those sides is the same (because it is the angle at R–T in each triangle)

Therefore

△QRT≅△TRS\triangle QRT \cong \triangle TRS

by the Side–Side–Side (SSS) property OR Side–Angle–Side (SAS) (since the angle between equal sides is the angle at T, which is common).