In order to determine the slope of a line, we need two known points (x1, y1) and (x2, y2), then we need to use the following expression:

In order to determine the slopes, we will use the expression above and choose two points that belong to the lines.
The slope of ST:

The slope of TU:

The slope of US:

In order to determine the length of a segment, we need to calculate the distance between the two endpoints of that segment. This is done by using the following formula:
![d=\sqrt[]{(y_2-y_1)^2+(x_2-x_1)^2}](https://img.qammunity.org/2023/formulas/mathematics/college/nkjymhkzx142t3t66rnvx6qo7qj0ya3b8k.png)
The length of ST is:
![\begin{gathered} d=\sqrt[]{(8-7)^2+(6-1)^2} \\ d=\sqrt[]{1^2+5^2} \\ d=\sqrt[]{1+25} \\ d=\sqrt[]{26}=5.1 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/wxxsoxvlpnokrgqdt81343dpyo1s4rjhe5.png)
The length of TU is:
![\begin{gathered} d=\sqrt[]{(-2-8)^2+(8-6)^2} \\ d=\sqrt[]{(-10)^2+(2)^2} \\ d=\sqrt[]{100+4} \\ d=\sqrt[]{104}=10.2 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/5qf5cfngj689t0nqzof1145b10vb9raajg.png)
The length of US is:
![\begin{gathered} d=\sqrt[]{(-2-7)^2+(8-1)^2} \\ d=\sqrt[]{(-9)^2+(7)^2} \\ d=\sqrt[]{81+49} \\ d=\sqrt[]{130} \\ d=11.4 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/2ls5tmecvsqnauo75agtr9x7r1swrm5h4d.png)
The triangle STU is scalene right.