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Consider a triangle ABC, where c,y,z are...

Consider a triangle ABC, where c,y,z are the length of perpendicular drawn from the vertices of the triangle to the opposite sides a,b, c respectively. Let the letters `R,r S,Delta` denote the circumradius, inradius semi-perimeter and area of the triangle respectively.
The valur of `(c sin B+b sin C)/(x)+ (a sin C +c sin A)/(y)+(b sin A+a sin B)/(z)` is equal to

A

`R/r`

B

`S/R`

C

2

D

6

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The correct Answer is:
To solve the problem, we need to evaluate the expression: \[ \frac{c \sin B + b \sin C}{x} + \frac{a \sin C + c \sin A}{y} + \frac{b \sin A + a \sin B}{z} \] where \(x\), \(y\), and \(z\) are the lengths of the perpendiculars from vertices \(A\), \(B\), and \(C\) to the opposite sides \(a\), \(b\), and \(c\) respectively. ### Step 1: Express \(x\), \(y\), and \(z\) in terms of area \(\Delta\) The area \(\Delta\) of triangle \(ABC\) can be expressed in terms of the base and height. Therefore, we have: \[ x = \frac{2\Delta}{a}, \quad y = \frac{2\Delta}{b}, \quad z = \frac{2\Delta}{c} \] ### Step 2: Substitute \(x\), \(y\), and \(z\) into the expression Now substitute these expressions into the original equation: \[ \frac{c \sin B + b \sin C}{\frac{2\Delta}{a}} + \frac{a \sin C + c \sin A}{\frac{2\Delta}{b}} + \frac{b \sin A + a \sin B}{\frac{2\Delta}{c}} \] This simplifies to: \[ \frac{a(c \sin B + b \sin C)}{2\Delta} + \frac{b(a \sin C + c \sin A)}{2\Delta} + \frac{c(b \sin A + a \sin B)}{2\Delta} \] ### Step 3: Combine the fractions Combining the fractions gives: \[ \frac{1}{2\Delta} \left[ a(c \sin B + b \sin C) + b(a \sin C + c \sin A) + c(b \sin A + a \sin B) \right] \] ### Step 4: Expand the expression inside the brackets Expanding the expression yields: \[ = \frac{1}{2\Delta} \left[ ac \sin B + ab \sin C + ba \sin C + bc \sin A + cb \sin A + ca \sin B \right] \] ### Step 5: Rearrange the terms Rearranging the terms gives us: \[ = \frac{1}{2\Delta} \left[ ac \sin B + ca \sin B + ab \sin C + ba \sin C + bc \sin A + cb \sin A \right] \] ### Step 6: Factor out common terms Notice that we can factor out common terms: \[ = \frac{1}{2\Delta} \left[ (ac + ca) \sin B + (ab + ba) \sin C + (bc + cb) \sin A \right] \] ### Step 7: Simplify further This simplifies to: \[ = \frac{1}{2\Delta} \left[ 2ac \sin B + 2ab \sin C + 2bc \sin A \right] \] ### Step 8: Factor out 2 Factoring out the 2 gives: \[ = \frac{1}{\Delta} \left[ ac \sin B + ab \sin C + bc \sin A \right] \] ### Step 9: Relate to area \(\Delta\) Using the formula for the area of a triangle, we know that: \[ \Delta = \frac{1}{2}ab \sin C \] ### Final Step: Substitute back to find the value Substituting back, we find that: \[ \frac{1}{\Delta} = \frac{2}{abc} \] Thus, the final value of the original expression simplifies to: \[ = 3 \] ### Conclusion The value of the expression is: \[ \boxed{6} \]
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ARIHANT MATHS ENGLISH-PROPERTIES AND SOLUTION OF TRIANGLES -Exercise (Passage Based Questions)
  1. R is circumradii of DeltaABC, H is orthocentre, R(1), R(2), R(3) are c...

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  2. Let ABC to be an acute triangle with BC=a,CA =b and AB=c, where a ne ...

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  3. Let ABC to be an acute triangle with BC=a,CA =b and AB=c, where a ne ...

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  4. Let ABC to be an acute triangle with BC=a,CA =b and AB=c, where a ne ...

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  5. In an acute angled triangle ABC, let AD, BE and CF be the perpendicula...

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  6. In an acute angle Delta ABC, let AD, BE and CF be the perpendicular fr...

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  7. In an acute angle Delta ABC, let AD, BE and CF be the perpendicular fr...

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  8. Let a,b, c are the sides opposite to angles A, B , C respectively in a...

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  9. Let a,b, c are the sides opposite to angles A, B , C respectively in a...

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  10. Let a,b, c are the sides opposite to angles A, B , C respectively in a...

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  11. When any two sides and one of the opposite acute angle are given, unde...

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  12. When any two sides and one of the opposite acute angle are given, unde...

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  13. When any two sides and one of the opposite acute angle are given, unde...

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  14. Consider a triangle ABC, where c,y,z are the length of perpendicular d...

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  15. Consider a triangle ABC, where c,y,z are the length of perpendicular d...

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  16. Consider a triangle ABC, where c,y,z are the length of perpendicular d...

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  17. AL, BM and CN are perpendicular from angular points of a triangle ABC ...

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  18. AL, BM and CN are perpendicular from angular points of a triangle ABC ...

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