Determine the lenth of side RS with points R(-1,7) and S(3,-1).
Determine the length of side ST with points S(3,-1) and T(9,2).
Determine the length of side RT with point R(-1,7) and T(9,2).
Since from the above calculation it can be observed that,
So, the triangle RST is a right angled triangle as pythagoras theorem is aplicable to the triangle RST.