In isosceles triangle TSR, ST = SR and angle TSR = 70 degrees. Calculate the measure of angle SRT.

Step 1: Calculate the base angles of the isosceles triangle $\triangle TSR$.
Given that $|ST| = |SR|$ and $m\angle TSR = 70^\circ$, $\triangle TSR$ is an isosceles triangle. The base angles opposite the equal sides are equal, so $m\angle STR = m\angle SRT$.
The sum of angles in a triangle is $180^\circ$.

$$m\angle STR + m\angle SRT + m\angle TSR = 180^\circ$$ $$2 \cdot m\angle SRT + 70^\circ = 180^\circ$$ $$2 \cdot m\angle SRT = 180^\circ - 70^\circ$$ $$$$