ANSWER
QR
EXPLANATION
The smallest triangle in the figure is SQR.
The largest triangle in the figure is PSR.
Both triangles are right-angled triangles.
Therefore, they have one set of corresponding angles which is This is because those two angles are equal (90 degrees).
We see therefore that RS in PSR (largest triangle) would correspond would QR in SQR (the smallest triangle) because they are both below the right angle.
