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The angles A,B and C of a DeltaABC are i...

The angles A,B and C of a `DeltaABC` are in A.PP. If AB=6, BC=7, then AC=

A

5 units

B

7 units

C

8 units

D

none of these

Text Solution

Verified by Experts

It is given that A, B and C are in A.P.
`therefore2B=A+C`
`rArr3B=A+B+C`
`rArr3B=pi` `[because A+B+C=pi]`
`rArrB=pi/3`
`rArrcosB=1/2`
`rArr(a^(2)+c^(2)-b^(2))/(2ac)-1/2rArr49+36-b^(2)=42rArrb=sqrt(43)`
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OBJECTIVE RD SHARMA ENGLISH-PROPERTIES OF TRIANGLES AND CIRCLES CONNECTED WITH THEM-Chapter Test
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  9. In a DeltaA B Csum(b+c)tanA/2tan((B-C)/2)=

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  11. In a DeltaABC, AD is the altitude from A. Given b gt c, angleC=23^(@)"...

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  12. If the angles A, B, C (in that order) of triangle ABC are in arithmeti...

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  13. If the radius of the incircle of a triangle withits sides 5k, 6k and 5...

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  14. Two sides of a triangle are 2sqrt2 and 2sqrt3cm and the angle opposite...

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  15. In a triangleABC, a=13cm, b=12 and c=5cm The distance of A from BC is

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  16. In a triangleABC,B=pi/8, C=(5pi)/(8). The altitude from A to the side ...

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  17. In DeltaABC, A = (2pi)/(3), b -c = 3 sqrt3 cm and " area of " Delta AB...

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  18. In DeltaABC if a=(b-c)sectheta then (2sqrt(bc))/(b-c)sin(A/2)=

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  20. If in DeltaABC, a=2b and A=3B, then A is equal to

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