Question 710453
Use Pythagorean theorem:
{{{c^2 = a^2 + b^2}}}
Since T is the right angle, it means that RS is the hypotenuse

{{{25^2= 7^2 + b^2}}}
{{{625= 49 + b^2}}}
{{{625-49= b^2}}}
{{{ 576= b^2}}}
{{{ sqrt(576)= b}}}
{{{ 24=b}}}


Answer: ST=24cm