Question

Show the points (1,-1)(5,2)&(9,5) cannot form a triangle

Answer 1

Step-by-step explanation:

By triangle formula in coordinate geometry,

$\frac{1}{2} (1(2 - 5) + 5( 5 + 1) + 9( - 1 - 2)) \\ \frac{1}{2} (1 \times ( - 3) + 5(6) + 9( - 3) \\ \frac{1}{2} ( - 3 + 30 - 27) \\ \frac{1}{2} (30 - 30) \\ \frac{1}{2} (0) \\ 0$

If the points are in straight line the they form zero which donot form a triangle(collinear)

HENCE PROVED