BE and CF are two equal altitudes of a triangle ABC. Using RHS congruence rule, prove that the triangle ABC is isosceles.

If the bisector of an angle of a triangle also bisects the opposite side, prove that the triangle is isosceles.

In triangle ABC , if cosA+sinA-(2)/(cosB+sinB)=0 then prove that triangle is isosceles right angled.

In a Delta ABC, if cos C = (sin A)/(2 sin B) , show that the triangle is isosceles.

In triangle ABC if 2sin^(2)C=2+cos2A+cos2B , then prove that triangle is right angled.

Prove that in triangle ABC, 2cos A cosB cos Cle(1)/(8) .

PQ is a vertical tower having P as the foot. A,B,C are three points in the horizontal plane through P. The angles of elevation of Q from A,B,C are equal and each is equal to theta . The sides of the triangle ABC are a,b,c, and area of the triangle ABC is del . Then prove that the height of the tower is (abc) tantheta/(4)dot

In a triangle ABC , bcosc +c cosB is:

BL and CM are medians of a triangle ABC right angled at A. Prove that 4(BL^(2)+ CM^(2))=5BC^(2)

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

A (veca), B (vecb) and C (vecc) are the vertices of triangle ABC and R(vecr) is any point in the plane of triangle ABC, then vecr, (veca xx vecb + vecb xx vecc + vecc xx veca ) is always equal to