Question

Which type of triangle is formed by joining the vertices A(-3, 6), B(2, 1), and C(9, 5)?

Answer 1

If you use the Pythagorean Theorem to find the length of the sides with A and B = to difference of X and Y of the points you'll find the lengths of the sides to be each different, therefore it is scalene. ex; difference between x coordinates of A and B is (-3 - 2) = -5, difference between y coordinates is (6 - 1) = 5, -5^2 + 5^2 = 50, sqrt 50 = 7.071, length of AB is 7.071. If two of the sides are equal in length, it is isosceles, and if all three are equal, it is equilateral. 

If you don't want an explanation, it's scalene. 

Here is a diagram:

Answer 2

The triangle formed is called a isocales triangle.
hope this helps