Geometry

Question Analysis:
This question tests fast right triangle proof strategies.
The main focus is verifying perpendicular sides using slope.

Key Concept Explanation:
A right triangle contains one right angle, which is proven by perpendicular sides.

Step-by-Step Solution:
Find slope of PQ, PR, and QR.
slope of PQ = 0 (horizontal line),
slope of PR is undefined (vertical line).
A horizontal and a vertical line are perpendicular.

Option Analysis:
A. Congruent sides suggest isosceles, not necessarily right triangle.
B. Correct. Perpe...