Home
Class 12
MATHS
In a Delta ABC, show that (a cos A+b co...

In a `Delta ABC, ` show that `(a cos A+b cos B+ c cos C)/(a+b+c)= (r )/(R )`

A

`R/r`

B

`r/R`

C

`R/(2r)`

D

`(2r)/R`

Text Solution

Verified by Experts

The correct Answer is:
B
Promotional Banner

Topper's Solved these Questions

  • PROPERTIES OF TRIANGLES

    ML KHANNA|Exercise Problem Set (4)(TRUE AND FALSE)|9 Videos

  • PROPERTIES OF TRIANGLES

    ML KHANNA|Exercise Problem Set (4)(FILL IN THE BLANKS)|3 Videos

  • PROPERTIES OF TRIANGLES

    ML KHANNA|Exercise Problem Set (3)(FILL IN THE BLANKS)|2 Videos

  • PROGRESSIONS

    ML KHANNA|Exercise MISCELLANEOUS EXERCISE (ASSERTION/REASON) |1 Videos

  • RECTANGULAR CARTESIAN CO-ORDINATE SYSTEM AND THE STRAIGHT LINE

    ML KHANNA|Exercise COMPREHENSION |11 Videos

Similar Questions

Explore conceptually related problems

In any Delta ABC, show that cos A+ cos B+ cos C = (1+ (r )/(R )).

In any Delta ABC, prove that :a cos A+b cos B+c cos C=2a sin B sin C

In a Delta ABC, the value of (a cos A+b cos B+c cos C)/(a+b+c) is equal to

In Delta ABC, show that (1-cos A+cos B+cos C)/(1-cos C+cos A+cos B)=tan((A)/(2))cot((C)/(2))

In Delta ABC, prove that :(c-b cos A)/(b-c cos A)=(cos B)/(cos C)

In any triangle ABC, prove that: a cos A+b cos B+c cos C=2a sin B sin C

In any Delta ABC, prove that : (cos A)/(b cos C+c cos B)+(cos B)/(c cos A+a cos C)+(cos C)/(c cos B+b cos A)=(a^(2)+b^(2)+c^(2))/(2abc)

In any Delta ABC, prove that: (cos A)/(b cos C+c cos B)+(cos B)/(c cos A+a cos C)+(cos C)/(a cos B+b cos A)=(a^(2)+b^(2)+c^(2))/(2abc)

Delta ABC,quad if a cos A+b cos B+c cos C=(2Delta)/(k) then k=

In any Delta ABC, prove that :a(b cos C-c cos B)=b^(2)-c^(2)

ML KHANNA-PROPERTIES OF TRIANGLES -Problem Set (4)(MULTIPLE CHOICE QUESTIONS)
  1. In a triangle if angleC=90^@ " then " R+r=

    Text Solution

    |

  2. In DeltaABC," if " angleC=90^(@)," then " (a+c)/(b)+(b+c)/(a) is equal...

    Text Solution

    |

  3. The in- radius of the triarigle formed by the axes and the line 4x + 3...

    Text Solution

    |

  4. In a triangle ABC , let angleC=(pi)/2. If r is the in-radius and R is ...

    Text Solution

    |

  5. In a triangle ABC right angled at B, the inradius r is equal to

    Text Solution

    |

  6. In an acute angled triangle which one of the following is true

    Text Solution

    |

  7. Two sides of a triangle are 2 and sqrt3 and the included angle is 30^@...

    Text Solution

    |

  8. Two sides of a triangle are the roots of the equation x^2 - 5x +6=0. I...

    Text Solution

    |

  9. In a triangle ABC if r1=R, then

    Text Solution

    |

  10. In a Delta ABC, show that (a cos A+b cos B+ c cos C)/(a+b+c)= (r )/(R...

    Text Solution

    |

  11. Which of the following pieces of data does not uniquely determine an a...

    Text Solution

    |

  12. If twice the square on the diameter of a circle is equal to sum of the...

    Text Solution

    |

  13. (r1-r)(r2+r3)=?

    Text Solution

    |

  14. Show that, 4 R r cos ""A/2cos ""B/2 cos ""C/2 =S

    Text Solution

    |

  15. if cos A+cosB+cosC=1+4sin(A/2).sin(B/2).sin(C/2) then cos A+cosB+co...

    Text Solution

    |

  16. In a !ABC cos^(2)A/2+cos^(2)B/2+cos^(2)C/2=

    Text Solution

    |

  17. r1/(bc)+r2/(ca)+r3/(ab)=

    Text Solution

    |

  18. Three circles whose radii are 2, 3, 4 units and having centres as C1,C...

    Text Solution

    |

  19. If r1, lt r2, lt r3 are the ex-radii of a right angled triangle and r1...

    Text Solution

    |

  20. For a regular polygon , let r and R be the radii of the inscribed and ...

    Text Solution

    |