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Question

Question: If the points (2*K, K*)(*K*, 2*K*) and (*K*, *K*) with \(K > 0\)enclose triangle of area 18 square u...

If the points (2K, K)(K, 2K) and (K, K) with K>0K > 0enclose triangle of area 18 square units then the centroid of triangle is equal to

A

(8, 8)

B

(4, 4)

C

(– 4, – 4)

D

(42,42)(4\sqrt{2},4\sqrt{2})

Answer

(8, 8)

Explanation

Solution

Δ=122KK1K2K1KK1=18\Delta = \frac{1}{2}\left| \begin{matrix} 2K & K & 1 \\ K & 2K & 1 \\ K & K & 1 \end{matrix} \right| = 18K22=18\frac{K^{2}}{2} = 18K=±6K = \pm 6. Consider K = +6 because K > 0, then the points (12, 6) (6,12) and (6,6).

Hence, centroid = (12+6+63,6+12+63)=(8,8)\left( \frac{12 + 6 + 6}{3},\frac{6 + 12 + 6}{3} \right) = (8,8)