Question

The fourth vertex D of a parallelogram ABCD whose three vertices are A( - 2, 3), B(6, 7) and C(8, 3) is 

A. (0, 1)  B. (0, - 1) C. (- 1, 0) D. (1, 0)

Answer 1

Given a parallelogram ABCD whose three vertices are;

A ( - 2, 3),

B (6, 7) and

C (8, 3)

Let the fourth vertex of parallelogram, D = (x₄, y₄) and L, M be the middle points of AC and BD, respectively

Since, mid - point of a line segment having points (x₁, y₁) and (x₂, y₂)

As we know ABCD is a parallelogram, therefore diagonals AC and BD will bisect each other.

So, L and M are the same points

→ 6 = 6 + x₄ and 6 = 7 + y₄

→ x₄ = 0 and y₄ = 6 – 7

∴ x₄ = 0 and y₄ = - 1

Hence, the fourth vertex of parallelogram is D = (x₄, y₄) = (0, 1)