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Three points P, Q, R lie on the side BC ...

Three points P, Q, R lie on the side BC of triangle ABC such that BP = PQ = QR = RC. If G be centroid of `DeltaABC` then what is ratio of areas of `DeltaPGR and DeltaABC`.

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To solve the problem, we need to find the ratio of the areas of triangle PGR to triangle ABC, given that the points P, Q, and R divide the side BC of triangle ABC into equal segments. ### Step-by-Step Solution: 1. **Identify the Points on BC**: Let the length of segment BC be divided into four equal parts by points P, Q, and R. Therefore, we can denote: - BP = PQ = QR = RC = x (where x is the length of each segment). - Thus, the total length BC = 4x. 2. **Determine the Centroid G**: The centroid G of triangle ABC divides each median in the ratio 2:1. Since G is the centroid, it will also divide the area of triangle ABC into three equal parts. 3. **Area of Triangle ABC**: Let the area of triangle ABC be denoted as Area(ABC). The centroid divides triangle ABC into three smaller triangles (AGB, AGC, and AGB), each having equal area: \[ \text{Area}(AGB) = \text{Area}(AGC) = \text{Area}(AGP) = \frac{1}{3} \text{Area}(ABC) \] 4. **Area of Triangle PGR**: Since P, Q, and R divide BC into equal segments, triangles APG, AQR, and APR will have equal areas. The area of triangle PGR can be calculated as follows: - The area of triangle APQ is equal to the area of triangle AQR, and since G is the centroid, the area of triangle PGR will be half of the area of triangle AQR. - Therefore, we can denote the area of triangle PGR as: \[ \text{Area}(PGR) = \text{Area}(AGP) + \text{Area}(AGR) = \frac{1}{3} \text{Area}(ABC) + \frac{1}{3} \text{Area}(ABC) = \frac{2}{3} \text{Area}(ABC) \] 5. **Calculate the Ratio**: Now, we can find the ratio of the areas of triangle PGR to triangle ABC: \[ \text{Ratio} = \frac{\text{Area}(PGR)}{\text{Area}(ABC)} = \frac{2}{3 \cdot 4} = \frac{2}{12} = \frac{1}{6} \] ### Final Answer: The ratio of the areas of triangle PGR to triangle ABC is \( \frac{1}{6} \).
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