Determine the lenth of side RS with points R(-1,7) and S(3,-1).
![\begin{gathered} RS=\sqrt[]{(3+1)^2+(-1-7)^2} \\ =\sqrt[]{16+64} \\ =\sqrt[]{80} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/r959cfx6e545e9b13ispkwt63fne3k10lw.png)
Determine the length of side ST with points S(3,-1) and T(9,2).
![\begin{gathered} ST=\sqrt[]{(2+1)^2+(9-3)^2} \\ =\sqrt[]{9+36} \\ =\sqrt[]{45} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/jdds953jaokzgls0gfl7w5jb7nq25l8y7w.png)
Determine the length of side RT with point R(-1,7) and T(9,2).
![\begin{gathered} RT=\sqrt[]{(2-7)^2+(9+1)^2} \\ =\sqrt[]{25+100} \\ =\sqrt[]{125} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/16qdnyhwumioepoqe7bhmor4jce0y2i502.png)
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.