In $\triangle ABC$, points P, Q and R are the mid-points of sides AB, BC and CA respectively. If area of $\triangle ABC$ is 20 sq. units, find the area of $\triangle PQR$.
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The medial triangle formed by joining midpoints of a triangle’s sides always has $\frac14$ the area of the original.
P, Q, R are midpoints of the sides, so $\triangle PQR$ is the medial triangle of $\triangle ABC$. The medial triangle’s area is always $\frac{1}{4}$ of the original triangle’s area.
Thus, Area$(PQR) = \frac{1}{4} \times 20 = 5$ sq. units.