Question

Two vertices of a triangle are (5, 4) and (–2, 4). If its centroid is (5, 6) then the third vertex has coordinates –

• A. (12, 10)
• B. (10, 12)
• C. (–10, 12)
• D. (12, –10)

Answer 1

Answer: (A)

(12, 10)

Answer 2

Let the third vertex be (x, y)

then centroid $\left( \frac{5 - 2 + x}{3},\frac{4 + 4 + y}{3} \right)$ = (5, 6)

Ž $\frac{3 + x}{3}$ = 5 and $\frac{8 + y}{3}$ = 6 Ž x = 12 y = 10

(12, 10)