In triangle ABC, the line joining the circumcenter and incenter is parallel to side AC, then `cosA+cosC` is equal to `-1` (b) `1` (c) `-2` (d) `2`

In any Delta ABC line joiningcircumcentre (O) and incentre (I) is parallel to AC, then OI is equal to

In triangle ABC, line joining the circumcenter and orthocentre is parallel to side AC, then the value of t a n AtanCi se q u a lto sqrt(3) (b) 3 (c) 3sqrt(3) (d) none of these

Let ABC be a triangle in which the line joining the circumecentre and incentre is parallel to base BC of the triangle. Then answer the following questions : If angleA=60^(@) , then Delta ABC is

Prove that the distance between the circumcenter and the incenter of triangle ABC is sqrt(R^2-2R r)

Prove that the distance between the circumcenter and the incenter of triangle ABC is sqrt(R^2-2R r)

In triangle A B C , if cosA+cosB+cosC=7/4, t h e n R/r is equal to 3/4 (b) 4/3 (c) 2/3 (d) 3/2

Show that the line joining the incenter to the circumcentre of triangle ABC is inclined to the side BC at an angle tan^(-1) ((cos B + cos C -1)/(sin C - sin B))

If sinthetaa n d-costheta are the roots of the equation a x^2-b x-c=0 , where a , ba n dc are the sides of a triangle ABC, then cosB is equal to 1-c/(2a) (b) 1-c/a 1+c/(c a) (d) 1+c/(3a)

The line segment joining the mid-points of two sides of triangles is parallel to the third side and is equal to ____ of its length.

In a triangle ABC , if cos A cos B + sin A sin B sin C = 1 , then a:b:c is equal to