In triangle ABC, if a = 2 and bc = 9, then prove that `R = 9//2Delta`

In a triangle ABC if r=3,R=6,r_(1)=9 then A=

In any triangle ABC, if 8R^(2) =a^(2) + b^(2) +c^(2) , prove that, the triangle is right angled.

In any triangle ABC If sinA : sinB: sinC=4:5:6,then prove that cos A :cosB: cosC=12:9:2.

In triangle ABC, AB = 5. BC = 9 and AC =7. The value of tan((A-B)/2)/tan((A+B)/2) is

If in a triangle ABC, (bc)/(2 cos A) = b^(2) + c^(2) - 2bc cos A then prove that the triangle must be isosceles.

If in a triangle ABC, (bc)/(2 cos A) = b^(2) + c^(2) - 2bc cos A then prove that the triangle must be isosceless

If in a triangle ABC, (bc)/(2 cos A) = b^(2) + c^(2) - 2bc cos A then prove that the triangle must be isosceles.

If in a triangle ABC, (bc)/(2 cos A) = b^(2) + c^(2) - 2bc cos A then prove that the triangle must be isosceless

In an equilateral triangle ABC, D is a point of BC such that 4BD = BC. Prove that 16AD^(2)=13BC^(2) .