Answer:
Yes, it is a right triangle.
Explanation:
slope of AB -> (5 - 3) / (0 + 6) = 2/6 -> 1/3
slope of BC -> (-1 - 5) / (2 - 0) = -6/2 -> -3
This already proves that it has a 90 degree angle at angle B because the slopes are inverse and reciprocal. A slope of 1/3 and a slope of -3 (inverse slopes) means that the lines are perpendicular to one another and form a 90 degree angle