In a triangle ABC,acosA+bcosB+ccosCa+b+c is equal torRRr2rRR2r

TrianglesABCandDEFare shown above. Which of the following is equal to the ratio ABBC​ ?

In fig., ABC and DBC are two isosceles triangles on the same base BC.Show that ∠ABD=∠ACD.

The sides of triangle ABC satisfy the equation 2a^2+4b^2+c^2=4ab+2ac. Then

ABC is an isosceles triangle with AB = AC and AD ⊥ BC. Is ∆ADB ≅ ∆ACD ?

ABC is an isosceles triangle with AB = AC. Draw AP ⊥ BC to show that∠ B = ∠ C