Question

Find the third vertex of a triangle, if two of its vertices are at (-3, 1) and (0, -2) and the centroid is at the origin.

Answer 1

Let the coordinates of the third vertex be (x, y)

Then, we know that the coordinates of centroid of the triangle are

Given that the centroid for the triangle is at the origin (0, 0)

⇒ x – 3 = 0 ⇒ y – 1 = 0

⇒ x = 3 ⇒ y = 1

Therefore, the coordinates of the third vertex is (3, 1).