Question

The triangle joining the points P(2, 7), Q(4, –1),R(–2, 6) is.

• A. Equilateral triangle
• B. Right-angled triangle
• C. Isosceles triangle
• D. Scalene triangle

Answer 1

Answer: (B)

Right-angled triangle

Answer 2

Since $P Q = \sqrt { 68 } , P R = \sqrt { 17 } , Q R = \sqrt { 85 }$

$\therefore P Q ^ { 2 } + P R ^ { 2 } = Q R ^ { 2 }$, i.e. right angled triangle.