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Show that, 4 R r cos ""A/2cos ""B/2 cos ...

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

A

s

B

`s^2`

C

`S^2`

D

S

Text Solution

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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