prove $a,b,c$ in A.P if $tandfrac{A}{2}=dfrac{5}{6}$ and $tandfrac{C}{2}=dfrac{2}{5}$
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In $Delta ABC$ , if $tandfrac{A}{2}=dfrac{5}{6}$ and $tandfrac{C}{2}=dfrac{2}{5}$ , then prove that the sides $a,b,c$ are in A.P. My Attempt $$ sin A=frac{2.5}{6}.frac{36}{61}=frac{60}{61}\ sin C=frac{2.2}{5}.frac{25}{29}=frac{20}{29}\ $$ it is solved in my reference some fomula involving $2s=a+b+c$ , can I prove it using the basic known properties of triangles ?
trigonometry triangle
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asked Jan 4 at 16:37
ss1729 ss1729
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