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If P1, P2, P3 be the perpendiculars from...

If `P_1, P_2, P_3` be the perpendiculars from the vertices of a triangle to the opposite sidės then are the following statements true or false ? If not true, write the corrrect answer.
`1/p_1 + 1/p+1/p_3=1/R`

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To determine whether the statement \( \frac{1}{P_1} + \frac{1}{P_2} + \frac{1}{P_3} = \frac{1}{R} \) is true or false, we will analyze the relationship between the perpendiculars from the vertices of a triangle to the opposite sides and the circumradius \( R \). ### Step-by-Step Solution: 1. **Identify the Perpendiculars**: Let \( P_1, P_2, P_3 \) be the lengths of the perpendiculars dropped from vertices \( A, B, C \) of triangle \( ABC \) to the opposite sides \( BC, CA, AB \) respectively. 2. **Area of the Triangle**: The area \( \Delta \) of triangle \( ABC \) can be expressed using the base and height: - Using side \( BC \) as the base: \[ \Delta = \frac{1}{2} \times a \times P_1 \] - Using side \( CA \) as the base: \[ \Delta = \frac{1}{2} \times b \times P_2 \] - Using side \( AB \) as the base: \[ \Delta = \frac{1}{2} \times c \times P_3 \] 3. **Expressing Perpendiculars**: From these area expressions, we can derive the formulas for the perpendiculars: - \( P_1 = \frac{2\Delta}{a} \) - \( P_2 = \frac{2\Delta}{b} \) - \( P_3 = \frac{2\Delta}{c} \) 4. **Finding the Reciprocals**: Now we find the reciprocals of the perpendiculars: \[ \frac{1}{P_1} = \frac{a}{2\Delta}, \quad \frac{1}{P_2} = \frac{b}{2\Delta}, \quad \frac{1}{P_3} = \frac{c}{2\Delta} \] 5. **Summing the Reciprocals**: Adding these reciprocals together: \[ \frac{1}{P_1} + \frac{1}{P_2} + \frac{1}{P_3} = \frac{a}{2\Delta} + \frac{b}{2\Delta} + \frac{c}{2\Delta} = \frac{a + b + c}{2\Delta} \] 6. **Relating to the Circumradius**: The circumradius \( R \) of triangle \( ABC \) is given by the formula: \[ R = \frac{abc}{4\Delta} \] Therefore, we can express \( \Delta \) in terms of \( R \): \[ \Delta = \frac{abc}{4R} \] 7. **Substituting Back**: Substitute \( \Delta \) back into the sum of reciprocals: \[ \frac{1}{P_1} + \frac{1}{P_2} + \frac{1}{P_3} = \frac{a + b + c}{2 \cdot \frac{abc}{4R}} = \frac{2R(a + b + c)}{abc} \] 8. **Conclusion**: The final expression does not simplify to \( \frac{1}{R} \). Instead, it shows that: \[ \frac{1}{P_1} + \frac{1}{P_2} + \frac{1}{P_3} = \frac{2R(a + b + c)}{abc} \] Thus, the statement \( \frac{1}{P_1} + \frac{1}{P_2} + \frac{1}{P_3} = \frac{1}{R} \) is **false**. ### Correct Answer: The correct relationship is: \[ \frac{1}{P_1} + \frac{1}{P_2} + \frac{1}{P_3} = \frac{2R(a + b + c)}{abc} \]
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