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If AD, BE , CF are internal bisectors of...

If AD, BE , CF are internal bisectors of the angles of `Delta ABC, " then " (cos A//2)/(AD) + (cos B//2)/(BE) + (cos C//2)/(CF)` =

A

`(abc)/(2s)`

B

`(2s)/(abc)`

C

`(ab + bc + ca)/(abc)`

D

`(a + b + c)/(abc)`

Text Solution

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The correct Answer is:
C
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AAKASH SERIES-PROPERTIES OF TRIANGLES-LECTURE SHEET EXERCISE - III (Straight Objective Type Question)
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  3. If AD, BE , CF are internal bisectors of the angles of Delta ABC, " th...

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  4. If two shorter sides of a triangle measure 9 and 18. If the internal a...

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  5. The internal angular bisectors of angles of a Delta^("le") ABC meets c...

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  6. In a triangle ABC bisector of lfloor C meets the side AB at D and circ...

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  7. In Delta ABC , the median AD divides angle BAC such that angle BAD : ...

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  8. In a triangle ABC, the median to the side BC is of length 1/sqrt(11 - ...

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  9. If AD, BE and CF are the medians of a triangle ABC, then AD^(2) + BE^(...

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  10. If in a triangle PQR , sin P, sin Q, sin R are in A.P., then

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  11. In DeltaABC, AD is the altitude from A, if b gt c, C=23^(0), AD=(abc)/...

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  12. Altitude AD of an equilateral triangle ABC is a diameter of circle. If...

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  13. A triangle is inscribed in a circle. The vertices of the triangle divi...

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  14. The base of a triangle is a and ratio of remaining two sides is r ( r ...

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  15. The area of the right angled triangle in terms of its circum radius an...

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  16. In a triangle ABC, D and E are the mid-points of BC, CA respectively. ...

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  17. If the bisector of the angle lfloor C of a triangle ABC cuts AB in D ...

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  18. Let ABC be an isosceles triangle with base BC. If 'r' is the radius o...

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  19. If a right angled Delta ABC of maximum area is inscribed within a cir...

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  20. P is a point inside a Delta ABC of area K (K gt 0). The lengths of pe...

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