Question

Please help with this geometry question

Answer 1

Explanation:

because they are congruent, all the angles and side lengths inside the triplets of items among the 3 triangles are equal.

so, PT = TR, which makes PTR an isoceles triangle.

and it also means that PS = SR.

and that makes ST the height in an isoceles triangle (splitting the baseline in half), and therefore, the angle PST = the angle TSR = 90°.