Given:
The vertices of a triangle ABC are A( 0, 2), B (2, 5), and C (−1, 7).
To find:
Part A: The length of each side of the triangle.
Part B: The slope of each side of the triangle.
Part C: Classify the triangle.
Solution:
Part A: The vertices of a triangle ABC are A( 0, 2), B (2, 5), and C (−1, 7).
Distance formula:

Using the distance formula, we get




Similarly,


And,


Therefore, the length of each side of the triangle are  .
.
Part B:
Slope formula:

Slope of side AB is:


Slope of side BC is:



Slope of side AC is:



Therefore, the slopes of sides AB, BC, AC are  respectively.
 respectively.
Part C:

Product of slopes of AB and BC is:

So, side AB and BC are perpendicular to each other.
Two sides of triangle ABC are equal and one angle is a right angle.
Therefore, the triangle ABC is an isosceles right triangle.